diff --git a/lib/bcoin/chain/chainentry.js b/lib/bcoin/chain/chainentry.js
index 51b3aa05..049ff1bd 100644
--- a/lib/bcoin/chain/chainentry.js
+++ b/lib/bcoin/chain/chainentry.js
@@ -14,7 +14,6 @@ var utils = require('../utils/utils');
 var assert = utils.assert;
 var BufferWriter = require('../utils/writer');
 var BufferReader = require('../utils/reader');
-var InvItem = bcoin.packets.InvItem;
 
 /**
  * Represents an entry in the chain. Unlike
@@ -633,7 +632,7 @@ ChainEntry.prototype.toHeaders = function toHeaders() {
  */
 
 ChainEntry.prototype.toInv = function toInv() {
-  return new InvItem(constants.inv.BLOCK, this.hash);
+  return new bcoin.invitem(constants.inv.BLOCK, this.hash);
 };
 
 /**
diff --git a/lib/bcoin/env.js b/lib/bcoin/env.js
index d69bfc4f..aafa378c 100644
--- a/lib/bcoin/env.js
+++ b/lib/bcoin/env.js
@@ -136,17 +136,22 @@ function Environment() {
   this.ldb = require('./db/ldb');
   this.rbt = require('./db/rbt');
 
+  // Script
+  this.script = require('./script/script');
+  this.opcode = require('./script/opcode');
+  this.stack = require('./script/stack');
+  this.witness = require('./script/witness');
+  this.program = require('./script/program');
+  this.sc = require('./script/sigcache');
+
   // Primitives
   this.bloom = require('./primitives/bloom');
-  this.script = require('./primitives/script');
-  this.opcode = this.script.Opcode;
-  this.stack = this.script.Stack;
-  this.witness = this.script.Witness;
   this.address = require('./primitives/address');
+  this.outpoint = require('./primitives/outpoint');
   this.input = require('./primitives/input');
-  this.outpoint = this.input.Outpoint;
   this.output = require('./primitives/output');
   this.coin = require('./primitives/coin');
+  this.invitem = require('./primitives/invitem');
   this.tx = require('./primitives/tx');
   this.mtx = require('./primitives/mtx');
   this.abstractblock = require('./primitives/abstractblock');
@@ -155,7 +160,9 @@ function Environment() {
   this.merkleblock = require('./primitives/merkleblock');
   this.headers = require('./primitives/headers');
   this.keyring = require('./primitives/keyring');
-  this.hd = require('./primitives/hd');
+
+  // HD
+  this.hd = require('./hd/hd');
 
   // Node
   this.logger = require('./node/logger');
@@ -167,7 +174,6 @@ function Environment() {
   // Net
   this.timedata = require('./net/timedata');
   this.packets = require('./net/packets');
-  this.invitem = this.packets.InvItem;
   this.bip150 = require('./net/bip150');
   this.bip151 = require('./net/bip151');
   this.bip152 = require('./net/bip152');
@@ -191,11 +197,10 @@ function Environment() {
   this.minerblock = require('./miner/minerblock');
 
   // Wallet
-  this.txdb = require('./wallet/txdb');
   this.wallet = require('./wallet/wallet');
-  this.account = this.wallet.Account;
+  this.account = require('./wallet/account');
   this.walletdb = require('./wallet/walletdb');
-  this.path = this.walletdb.Path;
+  this.path = require('./wallet/path');
 
   // HTTP
   this.http = require('./http');
@@ -203,9 +208,6 @@ function Environment() {
   // Workers
   this.workers = require('./workers/workers');
 
-  // Sigcache
-  this.sc = require('./sigcache');
-
   // Global Instances
   this.sigcache = new this.sc(0);
   this.time = new this.timedata();
diff --git a/lib/bcoin/hd/README.md b/lib/bcoin/hd/README.md
new file mode 100644
index 00000000..a0d6b080
--- /dev/null
+++ b/lib/bcoin/hd/README.md
@@ -0,0 +1,74 @@
+HD mnemonics and keys (BIP32, BIP39) for bcoin.
+
+Parts of this software were originally based on bitcore-lib:
+
+- https://github.com/bitpay/bitcore-lib/blob/master/lib/hdprivatekey.js
+- https://github.com/bitpay/bitcore-lib/blob/master/lib/hdpublickey.js
+- https://github.com/ryanxcharles/fullnode/blob/master/lib/bip32.js
+- https://github.com/bitpay/bitcore-mnemonic/blob/master/lib/mnemonic.js
+
+BIP32
+
+```
+Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
+https://github.com/bcoin-org/bcoin
+
+Copyright (c) 2013-2015 BitPay, Inc.
+
+Parts of this software are based on Bitcoin Core
+Copyright (c) 2009-2015 The Bitcoin Core developers
+
+Parts of this software are based on fullnode
+Copyright (c) 2014 Ryan X. Charles
+Copyright (c) 2014 reddit, Inc.
+
+Parts of this software are based on BitcoinJS
+Copyright (c) 2011 Stefan Thomas <justmoon@members.fsf.org>
+
+Parts of this software are based on BitcoinJ
+Copyright (c) 2011 Google Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+```
+
+BIP39
+
+```
+The MIT License (MIT)
+
+Copyright (c) 2014 BitPay
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+```
diff --git a/lib/bcoin/hd/hd.js b/lib/bcoin/hd/hd.js
new file mode 100644
index 00000000..41595638
--- /dev/null
+++ b/lib/bcoin/hd/hd.js
@@ -0,0 +1,253 @@
+/*!
+ * hd.js - hd keys for bcoin
+ * Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var constants = bcoin.constants;
+var LRU = require('../utils/lru');
+var Mnemonic = require('./mnemonic');
+var HDPrivateKey = require('./private');
+var HDPublicKey = require('./public');
+
+/**
+ * @exports HD
+ */
+
+var HD = exports;
+
+/**
+ * Instantiate an HD key (public or private) from an base58 string.
+ * @param {Base58String} xkey
+ * @returns {HDPrivateKey|HDPublicKey}
+ */
+
+HD.fromBase58 = function fromBase58(xkey) {
+  if (HDPrivateKey.isExtended(xkey))
+    return HDPrivateKey.fromBase58(xkey);
+  return HDPublicKey.fromBase58(xkey);
+};
+
+/**
+ * Generate an {@link HDPrivateKey}.
+ * @param {Object} options
+ * @param {Buffer?} options.privateKey
+ * @param {Buffer?} options.entropy
+ * @param {String?} network
+ * @returns {HDPrivateKey}
+ */
+
+HD.generate = function generate(options, network) {
+  return HDPrivateKey.generate(options, network);
+};
+
+/**
+ * Generate an {@link HDPrivateKey} from a seed.
+ * @param {Object|Mnemonic|Buffer} options - seed,
+ * mnemonic, mnemonic options.
+ * @param {String?} network
+ * @returns {HDPrivateKey}
+ */
+
+HD.fromSeed = function fromSeed(options, network) {
+  return HDPrivateKey.fromSeed(options, network);
+};
+
+/**
+ * Instantiate an hd private key from a mnemonic.
+ * @param {Mnemonic|Object} mnemonic
+ * @param {String?} network
+ * @returns {HDPrivateKey}
+ */
+
+HD.fromMnemonic = function fromMnemonic(options, network) {
+  return HDPrivateKey.fromMnemonic(options, network);
+};
+
+/**
+ * Instantiate an HD key from a jsonified key object.
+ * @param {Object} json - The jsonified transaction object.
+ * @returns {HDPrivateKey|HDPublicKey}
+ */
+
+HD.fromJSON = function fromJSON(json) {
+  if (json.xprivkey)
+    return HDPrivateKey.fromJSON(json);
+  return HDPublicKey.fromJSON(json);
+};
+
+/**
+ * Instantiate an HD key from serialized data.
+ * @param {Buffer} data
+ * @returns {HDPrivateKey|HDPublicKey}
+ */
+
+HD.fromRaw = function fromRaw(data) {
+  if (HDPrivateKey.hasPrefix(data))
+    return HDPrivateKey.fromRaw(data);
+  return HDPublicKey.fromRaw(data);
+};
+
+/**
+ * Instantiate HD key from extended serialized data.
+ * @param {Buffer} data
+ * @returns {HDPrivateKey|HDPublicKey}
+ */
+
+HD.fromExtended = function fromExtended(data) {
+  if (HDPrivateKey.hasPrefix(data))
+    return HDPrivateKey.fromExtended(data);
+  return HDPublicKey.fromRaw(data);
+};
+
+/**
+ * Generate an hdkey from any number of options.
+ * @param {Object|Mnemonic|Buffer} options - mnemonic, mnemonic
+ * options, seed, or base58 key.
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey|HDPublicKey}
+ */
+
+HD.from = function from(options, network) {
+  var xkey;
+
+  assert(options, 'Options required.');
+
+  if (options.xkey)
+    xkey = options.xkey;
+  else if (options.xpubkey)
+    xkey = options.xpubkey;
+  else if (options.xprivkey)
+    xkey = options.xprivkey;
+  else
+    xkey = options;
+
+  if (HD.isExtended(xkey))
+    return HD.fromBase58(xkey);
+
+  if (HD.hasPrefix(options))
+    return HD.fromRaw(options);
+
+  return HD.fromMnemonic(options, network);
+};
+
+/**
+ * Test whether an object is in the form of a base58 hd key.
+ * @param {String} data
+ * @returns {Boolean}
+ */
+
+HD.isExtended = function isExtended(data) {
+  return HDPrivateKey.isExtended(data)
+    || HDPublicKey.isExtended(data);
+};
+
+/**
+ * Test whether an object is in the form of a serialized hd key.
+ * @param {Buffer} data
+ * @returns {NetworkType}
+ */
+
+HD.hasPrefix = function hasPrefix(data) {
+  return HDPrivateKey.hasPrefix(data)
+    || HDPublicKey.hasPrefix(data);
+};
+
+/**
+ * Parse a derivation path and return an array of indexes.
+ * @see https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
+ * @param {String} path
+ * @param {Number?} max - Max index.
+ * @returns {Number[]}
+ */
+
+HD.parsePath = function parsePath(path, max) {
+  var parts = path.split('/');
+  var root = parts.shift();
+  var result = [];
+  var i, hardened, index;
+
+  if (max == null)
+    max = constants.hd.MAX_INDEX;
+
+  if (root !== 'm'
+      && root !== 'M'
+      && root !== 'm\''
+      && root !== 'M\'') {
+    throw new Error('Bad path root.');
+  }
+
+  for (i = 0; i < parts.length; i++) {
+    index = parts[i];
+    hardened = index[index.length - 1] === '\'';
+
+    if (hardened)
+      index = index.slice(0, -1);
+
+    if (!/^\d+$/.test(index))
+      throw new Error('Non-number path index.');
+
+    index = parseInt(index, 10);
+
+    if (hardened)
+      index += constants.hd.HARDENED;
+
+    if (!(index >= 0 && index < max))
+      throw new Error('Index out of range.');
+
+    result.push(index);
+  }
+
+  return result;
+};
+
+/**
+ * LRU cache to avoid deriving keys twice.
+ * @type {LRU}
+ */
+
+HD.cache = new LRU(500);
+
+/**
+ * Test whether an object is an HD key.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HD.isHD = function isHD(obj) {
+  return HDPrivateKey.isHDPrivateKey(obj)
+    || HDPublicKey.isHDPublicKey(obj);
+};
+
+/**
+ * Test whether an object is an HD private key.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HD.isPrivate = function isPrivate(obj) {
+  return HDPrivateKey.isHDPrivateKey(obj);
+};
+
+/**
+ * Test whether an object is an HD public key.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HD.isPublic = function isPublic(obj) {
+  return HDPublicKey.isHDPublicKey(obj);
+};
+
+/*
+ * Expose
+ */
+
+HD.Mnemonic = Mnemonic;
+HD.PrivateKey = HDPrivateKey;
+HD.PublicKey = HDPublicKey;
diff --git a/lib/bcoin/hd/mnemonic.js b/lib/bcoin/hd/mnemonic.js
new file mode 100644
index 00000000..9bb0f787
--- /dev/null
+++ b/lib/bcoin/hd/mnemonic.js
@@ -0,0 +1,542 @@
+/*!
+ * mnemonic.js - hd mnemonics for bcoin
+ * Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var ec = require('../crypto/ec');
+var assert = utils.assert;
+var constants = bcoin.constants;
+var BufferWriter = require('../utils/writer');
+var BufferReader = require('../utils/reader');
+var HD = require('./hd');
+var unorm;
+
+/**
+ * HD Mnemonic
+ * @exports Mnemonic
+ * @constructor
+ * @param {Object} options
+ * @param {Number?} options.bit - Bits of entropy (Must
+ * be a multiple of 8) (default=128).
+ * @param {Buffer?} options.entropy - Entropy bytes. Will
+ * be generated with `options.bits` bits of entropy
+ * if not present.
+ * @param {String?} options.phrase - Mnemonic phrase (will
+ * be generated if not present).
+ * @param {String?} options.passphrase - Optional salt for
+ * key stretching (empty string if not present).
+ * @param {String?} options.language - Language.
+ */
+
+function Mnemonic(options) {
+  if (!(this instanceof Mnemonic))
+    return new Mnemonic(options);
+
+  this.bits = constants.hd.MIN_ENTROPY;
+  this.language = 'english';
+  this.entropy = null;
+  this.phrase = null;
+  this.passphrase = '';
+
+  if (options)
+    this.fromOptions(options);
+}
+
+/**
+ * List of languages.
+ * @const {String[]}
+ * @default
+ */
+
+Mnemonic.languages = [
+  'simplified chinese',
+  'traditional chinese',
+  'english',
+  'french',
+  'italian',
+  'japanese'
+];
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+Mnemonic.prototype.fromOptions = function fromOptions(options) {
+  if (typeof options === 'string')
+    options = { phrase: options };
+
+  if (options.bits != null) {
+    assert(utils.isNumber(options.bits));
+    assert(options.bits >= constants.hd.MIN_ENTROPY);
+    assert(options.bits <= constants.hd.MAX_ENTROPY);
+    assert(options.bits % 32 === 0);
+    this.bits = options.bits;
+  }
+
+  if (options.language) {
+    assert(typeof options.language === 'string');
+    assert(Mnemonic.languages.indexOf(options.language) !== -1);
+    this.language = options.language;
+  }
+
+  if (options.passphrase) {
+    assert(typeof options.passphrase === 'string');
+    this.passphrase = options.passphrase;
+  }
+
+  if (options.phrase) {
+    this.fromPhrase(options.phrase);
+    return this;
+  }
+
+  if (options.entropy) {
+    this.fromEntropy(options.entropy);
+    return this;
+  }
+
+  return this;
+};
+
+/**
+ * Instantiate mnemonic from options.
+ * @param {Object} options
+ * @returns {Mnemonic}
+ */
+
+Mnemonic.fromOptions = function fromOptions(options) {
+  return new Mnemonic().fromOptions(options);
+};
+
+/**
+ * Destroy the mnemonic (zeroes entropy).
+ */
+
+Mnemonic.prototype.destroy = function destroy() {
+  this.bits = constants.hd.MIN_ENTROPY;
+  this.language = 'english';
+  if (this.entropy) {
+    this.entropy.fill(0);
+    this.entropy = null;
+  }
+  this.phrase = null;
+  this.passphrase = '';
+};
+
+/**
+ * Generate the seed.
+ * @param {String?} passphrase
+ * @returns {Buffer} pbkdf2 seed.
+ */
+
+Mnemonic.prototype.toSeed = function toSeed(passphrase) {
+  if (!passphrase)
+    passphrase = this.passphrase;
+
+  this.passphrase = passphrase;
+
+  return utils.pbkdf2Sync(
+    nfkd(this.getPhrase()),
+    nfkd('mnemonic' + passphrase),
+    2048, 64, 'sha512');
+};
+
+/**
+ * Generate seed and create an hd private key.
+ * @param {String?} passphrase
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey}
+ */
+
+Mnemonic.prototype.toKey = function toKey(passphrase, network) {
+  var seed = this.toSeed(passphrase);
+  var key = HD.PrivateKey.fromSeed(seed, network);
+  key.mnemonic = this;
+  return key;
+};
+
+/**
+ * Get or generate entropy.
+ * @returns {Buffer}
+ */
+
+Mnemonic.prototype.getEntropy = function getEntropy() {
+  if (!this.entropy)
+    this.entropy = ec.random(this.bits / 8);
+
+  assert(this.bits / 8 === this.entropy.length);
+
+  return this.entropy;
+};
+
+/**
+ * Generate a mnemonic phrase from chosen language.
+ * @returns {String}
+ */
+
+Mnemonic.prototype.getPhrase = function getPhrase() {
+  var i, j, phrase, wordlist, bits, entropy, index, pos, oct, bit;
+
+  if (this.phrase)
+    return this.phrase;
+
+  phrase = [];
+  wordlist = Mnemonic.getWordlist(this.language);
+
+  entropy = this.getEntropy();
+  bits = this.bits;
+
+  // Append the hash to the entropy to
+  // make things easy when grabbing
+  // the checksum bits.
+  entropy = Buffer.concat([entropy, utils.sha256(entropy)]);
+
+  // Include the first `ENT / 32` bits
+  // of the hash (the checksum).
+  bits += bits / 32;
+
+  // Build the mnemonic by reading
+  // 11 bit indexes from the entropy.
+  for (i = 0; i < bits / 11; i++) {
+    index = 0;
+    for (j = 0; j < 11; j++) {
+      pos = i * 11 + j;
+      bit = pos % 8;
+      oct = (pos - bit) / 8;
+      index <<= 1;
+      index |= (entropy[oct] >>> (7 - bit)) & 1;
+    }
+    phrase.push(wordlist[index]);
+  }
+
+  // Japanese likes double-width spaces.
+  if (this.language === 'japanese')
+    phrase = phrase.join('\u3000');
+  else
+    phrase = phrase.join(' ');
+
+  this.phrase = phrase;
+
+  return phrase;
+};
+
+/**
+ * Inject properties from phrase.
+ * @private
+ * @param {String} phrase
+ */
+
+Mnemonic.prototype.fromPhrase = function fromPhrase(phrase) {
+  var i, j, bits, pos, oct, bit, b, ent, entropy, lang;
+  var chk, word, wordlist, index, cbits, cbytes, words;
+
+  assert(typeof phrase === 'string');
+
+  words = phrase.split(/[ \u3000]+/);
+  bits = words.length * 11;
+  cbits = bits % 32;
+  cbytes = Math.ceil(cbits / 8);
+  bits -= cbits;
+
+  assert(bits >= constants.hd.MIN_ENTROPY);
+  assert(bits <= constants.hd.MAX_ENTROPY);
+  assert(bits % 32 === 0);
+  assert(cbits !== 0, 'Invalid checksum.');
+
+  ent = new Buffer(Math.ceil((bits + cbits) / 8));
+  ent.fill(0);
+
+  lang = Mnemonic.getLanguage(words[0]);
+  wordlist = Mnemonic.getWordlist(lang);
+
+  for (i = 0; i < words.length; i++) {
+    word = words[i];
+    index = wordlist.indexOf(word);
+
+    if (index === -1)
+      throw new Error('Could not find word.');
+
+    for (j = 0; j < 11; j++) {
+      pos = i * 11 + j;
+      bit = pos % 8;
+      oct = (pos - bit) / 8;
+      b = (index >>> (10 - j)) & 1;
+      ent[oct] |= b << (7 - bit);
+    }
+  }
+
+  entropy = ent.slice(0, ent.length - cbytes);
+  ent = ent.slice(ent.length - cbytes);
+  chk = utils.sha256(entropy);
+
+  for (i = 0; i < cbits; i++) {
+    bit = i % 8;
+    oct = (i - bit) / 8;
+    b = (ent[oct] >>> (7 - bit)) & 1;
+    j = (chk[oct] >>> (7 - bit)) & 1;
+    if (b !== j)
+      throw new Error('Invalid checksum.');
+  }
+
+  assert(bits / 8 === entropy.length);
+
+  this.bits = bits;
+  this.language = lang;
+  this.entropy = entropy;
+  this.phrase = phrase;
+
+  return this;
+};
+
+/**
+ * Instantiate mnemonic from a phrase (validates checksum).
+ * @param {String} phrase
+ * @returns {Mnemonic}
+ * @throws on bad checksum
+ */
+
+Mnemonic.fromPhrase = function fromPhrase(phrase) {
+  return new Mnemonic().fromPhrase(phrase);
+};
+
+/**
+ * Inject properties from entropy.
+ * @private
+ * @param {Buffer} entropy
+ * @param {String?} lang
+ */
+
+Mnemonic.prototype.fromEntropy = function fromEntropy(entropy, lang) {
+  assert(Buffer.isBuffer(entropy));
+  assert(entropy.length * 8 >= constants.hd.MIN_ENTROPY);
+  assert(entropy.length * 8 <= constants.hd.MAX_ENTROPY);
+  assert((entropy.length * 8) % 32 === 0);
+  assert(!lang || Mnemonic.languages.indexOf(lang) !== -1);
+
+  this.entropy = entropy;
+  this.bits = entropy.length * 8;
+
+  if (lang)
+    this.language = lang;
+
+  return this;
+};
+
+/**
+ * Instantiate mnemonic from entropy.
+ * @param {Buffer} entropy
+ * @param {String?} lang
+ * @returns {Mnemonic}
+ */
+
+Mnemonic.fromEntropy = function fromEntropy(entropy, lang) {
+  return new Mnemonic().fromEntropy(entropy, lang);
+};
+
+/**
+ * Determine a single word's language.
+ * @param {String} word
+ * @returns {String} Language.
+ * @throws on not found.
+ */
+
+Mnemonic.getLanguage = function getLanguage(word) {
+  var i, lang, wordlist;
+
+  for (i = 0; i < Mnemonic.languages.length; i++) {
+    lang = Mnemonic.languages[i];
+    wordlist = Mnemonic.getWordlist(lang);
+    if (wordlist.indexOf(word) !== -1)
+      return lang;
+  }
+
+  throw new Error('Could not determine language.');
+};
+
+/**
+ * Retrieve the wordlist for a language.
+ * @param {String} language
+ * @returns {String[]}
+ */
+
+Mnemonic.getWordlist = function getWordlist(language) {
+  switch (language) {
+    case 'simplified chinese':
+      return require('../../../etc/chinese-simplified.js');
+    case 'traditional chinese':
+      return require('../../../etc/chinese-traditional.js');
+    case 'english':
+      return require('../../../etc/english.js');
+    case 'french':
+      return require('../../../etc/french.js');
+    case 'italian':
+      return require('../../../etc/italian.js');
+    case 'japanese':
+      return require('../../../etc/japanese.js');
+    default:
+      throw new Error('Unknown language: ' + language);
+  }
+};
+
+/**
+ * Convert mnemonic to a json-friendly object.
+ * @returns {Object}
+ */
+
+Mnemonic.prototype.toJSON = function toJSON() {
+  return {
+    bits: this.bits,
+    language: this.language,
+    entropy: this.getEntropy().toString('hex'),
+    phrase: this.getPhrase(),
+    passphrase: this.passphrase
+  };
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {Object} json
+ */
+
+Mnemonic.prototype.fromJSON = function fromJSON(json) {
+  assert(utils.isNumber(json.bits));
+  assert(typeof json.language === 'string');
+  assert(typeof json.entropy === 'string');
+  assert(typeof json.phrase === 'string');
+  assert(typeof json.passphrase === 'string');
+  assert(json.bits >= constants.hd.MIN_ENTROPY);
+  assert(json.bits <= constants.hd.MAX_ENTROPY);
+  assert(json.bits % 32 === 0);
+  assert(json.bits / 8 === json.entropy.length / 2);
+
+  this.bits = json.bits;
+  this.language = json.language;
+  this.entropy = new Buffer(json.entropy, 'hex');
+  this.phrase = json.phrase;
+  this.passphrase = json.passphrase;
+
+  return this;
+};
+
+/**
+ * Instantiate mnemonic from json object.
+ * @param {Object} json
+ * @returns {Mnemonic}
+ */
+
+Mnemonic.fromJSON = function fromJSON(json) {
+  return new Mnemonic().fromJSON(json);
+};
+
+/**
+ * Serialize mnemonic.
+ * @returns {Buffer}
+ */
+
+Mnemonic.prototype.toRaw = function toRaw(writer) {
+  var p = new BufferWriter(writer);
+  var lang = Mnemonic.languages.indexOf(this.language);
+
+  assert(lang !== -1);
+
+  p.writeU16(this.bits);
+  p.writeU8(lang);
+  p.writeBytes(this.getEntropy());
+  p.writeVarString(this.getPhrase(), 'utf8');
+  p.writeVarString(this.passphrase, 'utf8');
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} data
+ */
+
+Mnemonic.prototype.fromRaw = function fromRaw(data) {
+  var p = new BufferReader(data);
+
+  this.bits = p.readU16();
+  this.language = Mnemonic.languages[p.readU8()];
+  this.entropy = p.readBytes(this.bits / 8);
+  this.phrase = p.readVarString('utf8');
+  this.passphrase = p.readVarString('utf8');
+
+  assert(this.language);
+  assert(this.bits >= constants.hd.MIN_ENTROPY);
+  assert(this.bits <= constants.hd.MAX_ENTROPY);
+  assert(this.bits % 32 === 0);
+
+  return this;
+};
+
+/**
+ * Instantiate mnemonic from serialized data.
+ * @param {Buffer} data
+ * @returns {Mnemonic}
+ */
+
+Mnemonic.fromRaw = function fromRaw(data) {
+  return new Mnemonic().fromRaw(data);
+};
+
+/**
+ * Convert the mnemonic to a string.
+ * @returns {String}
+ */
+
+Mnemonic.prototype.toString = function toString() {
+  return this.getPhrase();
+};
+
+/**
+ * Inspect the mnemonic.
+ * @returns {String}
+ */
+
+Mnemonic.prototype.inspect = function inspect() {
+  return '<Mnemonic: ' + this.getPhrase() + '>';
+};
+
+/**
+ * Test whether an object is a Mnemonic.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+Mnemonic.isMnemonic = function isMnemonic(obj) {
+  return obj
+    && typeof obj.bits === 'number'
+    && typeof obj.toSeed === 'function';
+};
+
+/*
+ * Helpers
+ */
+
+function nfkd(str) {
+  if (str.normalize)
+    return str.normalize('NFKD');
+
+  if (!unorm)
+    unorm = require('../../../vendor/unorm');
+
+  return unorm.nfkd(str);
+}
+
+/*
+ * Expose
+ */
+
+module.exports = Mnemonic;
diff --git a/lib/bcoin/hd/private.js b/lib/bcoin/hd/private.js
new file mode 100644
index 00000000..818c0b31
--- /dev/null
+++ b/lib/bcoin/hd/private.js
@@ -0,0 +1,794 @@
+/*!
+ * private.js - hd private keys for bcoin
+ * Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var ec = require('../crypto/ec');
+var assert = utils.assert;
+var constants = bcoin.constants;
+var networks = bcoin.networks;
+var BufferWriter = require('../utils/writer');
+var BufferReader = require('../utils/reader');
+var HD = require('./hd');
+
+/*
+ * Constants
+ */
+
+var FINGER_PRINT = new Buffer('00000000', 'hex');
+
+/**
+ * HDPrivateKey
+ * @exports HDPrivateKey
+ * @constructor
+ * @param {Object|Base58String} options
+ * @param {Base58String?} options.xkey - Serialized base58 key.
+ * @param {Mnemonic?} options.mnemonic
+ * @param {Number?} options.depth
+ * @param {Buffer?} options.parentFingerPrint
+ * @param {Number?} options.childIndex
+ * @param {Buffer?} options.chainCode
+ * @param {Buffer?} options.privateKey
+ * @property {Network} network
+ * @property {Base58String} xprivkey
+ * @property {Base58String} xpubkey
+ * @property {Mnemonic?} mnemonic
+ * @property {Number} depth
+ * @property {Buffer} parentFingerPrint
+ * @property {Number} childIndex
+ * @property {Buffer} chainCode
+ * @property {Buffer} privateKey
+ * @property {HDPublicKey} hdPublicKey
+ */
+
+function HDPrivateKey(options) {
+  if (!(this instanceof HDPrivateKey))
+    return new HDPrivateKey(options);
+
+  this.network = bcoin.network.get();
+  this.depth = 0;
+  this.parentFingerPrint = FINGER_PRINT;
+  this.childIndex = 0;
+  this.chainCode = constants.ZERO_HASH;
+  this.privateKey = constants.ZERO_HASH;
+
+  this.publicKey = constants.ZERO_KEY;
+  this.fingerPrint = null;
+
+  this.mnemonic = null;
+
+  this._xprivkey = null;
+
+  this.hdPrivateKey = this;
+  this._hdPublicKey = null;
+
+  if (options)
+    this.fromOptions(options);
+}
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+HDPrivateKey.prototype.fromOptions = function fromOptions(options) {
+  assert(options, 'No options for HD private key.');
+  assert(utils.isNumber(options.depth));
+  assert(Buffer.isBuffer(options.parentFingerPrint));
+  assert(utils.isNumber(options.childIndex));
+  assert(Buffer.isBuffer(options.chainCode));
+  assert(Buffer.isBuffer(options.privateKey));
+  assert(options.depth <= 0xff, 'Depth is too high.');
+
+  if (options.network)
+    this.network = bcoin.network.get(options.network);
+
+  this.depth = options.depth;
+  this.parentFingerPrint = options.parentFingerPrint;
+  this.childIndex = options.childIndex;
+  this.chainCode = options.chainCode;
+  this.privateKey = options.privateKey;
+  this.publicKey = ec.publicKeyCreate(options.privateKey, true);
+
+  if (options.mnemonic) {
+    assert(options.mnemonic instanceof HD.Mnemonic);
+    this.mnemonic = options.mnemonic;
+  }
+
+  if (options.xprivkey) {
+    assert(typeof options.xprivkey === 'string');
+    this._xprivkey = options.xprivkey;
+  }
+
+  return this;
+};
+
+/**
+ * Instantiate HD private key from options object.
+ * @param {Object} options
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromOptions = function fromOptions(options) {
+  return new HDPrivateKey().fromOptions(options);
+};
+
+HDPrivateKey.prototype.__defineGetter__('hdPublicKey', function() {
+  var key = this._hdPublicKey;
+
+  if (!key) {
+    key = new HD.PublicKey();
+    key.network = this.network;
+    key.depth = this.depth;
+    key.parentFingerPrint = this.parentFingerPrint;
+    key.childIndex = this.childIndex;
+    key.chainCode = this.chainCode;
+    key.publicKey = this.publicKey;
+    this._hdPublicKey = key;
+  }
+
+  return key;
+});
+
+HDPrivateKey.prototype.__defineGetter__('xprivkey', function() {
+  if (!this._xprivkey)
+    this._xprivkey = this.toBase58();
+  return this._xprivkey;
+});
+
+HDPrivateKey.prototype.__defineGetter__('xpubkey', function() {
+  return this.hdPublicKey.xpubkey;
+});
+
+/**
+ * Destroy the key (zeroes chain code, privkey, and pubkey).
+ * @param {Boolean} pub - Destroy hd public key as well.
+ */
+
+HDPrivateKey.prototype.destroy = function destroy(pub) {
+  this.depth = 0;
+  this.parentFingerPrint.fill(0);
+  this.childIndex = 0;
+  this.chainCode.fill(0);
+  this.privateKey.fill(0);
+  this.publicKey.fill(0);
+
+  if (this.fingerPrint) {
+    this.fingerPrint.fill(0);
+    this.fingerPrint = null;
+  }
+
+  if (this._hdPublicKey) {
+    if (pub)
+      this._hdPublicKey.destroy();
+    this._hdPublicKey = null;
+  }
+
+  this._xprivkey = null;
+
+  if (this.mnemonic) {
+    this.mnemonic.destroy();
+    this.mnemonic = null;
+  }
+};
+
+/**
+ * Derive a child key.
+ * @param {Number|String} - Child index or path.
+ * @param {Boolean?} hardened - Whether the derivation should be hardened.
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.prototype.derive = function derive(index, hardened) {
+  var p, id, data, hash, left, right, key, child;
+
+  if (typeof index === 'string')
+    return this.derivePath(index);
+
+  hardened = index >= constants.hd.HARDENED ? true : hardened;
+
+  if (index < constants.hd.HARDENED && hardened)
+    index += constants.hd.HARDENED;
+
+  if (!(index >= 0 && index < constants.hd.MAX_INDEX))
+    throw new Error('Index out of range.');
+
+  if (this.depth >= 0xff)
+    throw new Error('Depth too high.');
+
+  id = this.getID(index);
+  child = HD.cache.get(id);
+
+  if (child)
+    return child;
+
+  p = new BufferWriter();
+
+  if (hardened) {
+    p.writeU8(0);
+    p.writeBytes(this.privateKey);
+    p.writeU32BE(index);
+  } else {
+    p.writeBytes(this.publicKey);
+    p.writeU32BE(index);
+  }
+
+  data = p.render();
+
+  hash = utils.hmac('sha512', data, this.chainCode);
+  left = hash.slice(0, 32);
+  right = hash.slice(32, 64);
+
+  try {
+    key = ec.privateKeyTweakAdd(this.privateKey, left);
+  } catch (e) {
+    return this.derive(index + 1);
+  }
+
+  if (!this.fingerPrint)
+    this.fingerPrint = utils.hash160(this.publicKey).slice(0, 4);
+
+  child = new HDPrivateKey();
+  child.network = this.network;
+  child.depth = this.depth + 1;
+  child.parentFingerPrint = this.fingerPrint;
+  child.childIndex = index;
+  child.chainCode = right;
+  child.privateKey = key;
+  child.publicKey = ec.publicKeyCreate(key, true);
+
+  HD.cache.set(id, child);
+
+  return child;
+};
+
+/**
+ * Unique HD key ID.
+ * @private
+ * @param {Number} index
+ * @returns {String}
+ */
+
+HDPrivateKey.prototype.getID = function getID(index) {
+  return this.network.keyPrefix.xprivkey58
+    + this.publicKey.toString('hex')
+    + index;
+};
+
+/**
+ * Derive a BIP44 account key.
+ * @param {Number} accountIndex
+ * @returns {HDPrivateKey}
+ * @throws Error if key is not a master key.
+ */
+
+HDPrivateKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex) {
+  assert(utils.isNumber(accountIndex), 'Account index must be a number.');
+  assert(this.isMaster(), 'Cannot derive account index.');
+  return this
+    .derive(44, true)
+    .derive(this.network.type === 'main' ? 0 : 1, true)
+    .derive(accountIndex, true);
+};
+
+/**
+ * Derive a BIP45 purpose key.
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.prototype.derivePurpose45 = function derivePurpose45() {
+  assert(this.isMaster(), 'Cannot derive purpose 45.');
+  return this.derive(45, true);
+};
+
+/**
+ * Test whether the key is a master key.
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.prototype.isMaster = function isMaster() {
+  return this.depth === 0
+    && this.childIndex === 0
+    && this.parentFingerPrint.readUInt32LE(0, true) === 0;
+};
+
+/**
+ * Test whether the key is (most likely) a BIP44 account key.
+ * @param {Number?} accountIndex
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.prototype.isAccount44 = function isAccount44(accountIndex) {
+  if (accountIndex != null) {
+    if (this.childIndex !== constants.hd.HARDENED + accountIndex)
+      return false;
+  }
+  return this.depth === 3 && this.childIndex >= constants.hd.HARDENED;
+};
+
+/**
+ * Test whether the key is a BIP45 purpose key.
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.prototype.isPurpose45 = function isPurpose45() {
+  return this.depth === 1 && this.childIndex === constants.hd.HARDENED + 45;
+};
+
+/**
+ * Test whether an object is in the form of a base58 xprivkey.
+ * @param {String} data
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.isExtended = function isExtended(data) {
+  var i, type, prefix;
+
+  if (typeof data !== 'string')
+    return false;
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xprivkey58;
+    if (data.indexOf(prefix) === 0)
+      return true;
+  }
+
+  return false;
+};
+
+/**
+ * Test whether a buffer has a valid network prefix.
+ * @param {Buffer} data
+ * @returns {NetworkType}
+ */
+
+HDPrivateKey.hasPrefix = function hasPrefix(data) {
+  var i, version, prefix, type;
+
+  if (!Buffer.isBuffer(data))
+    return false;
+
+  version = data.readUInt32BE(0, true);
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xprivkey;
+    if (version === prefix)
+      return type;
+  }
+
+  return false;
+};
+
+/**
+ * Test whether a string is a valid path.
+ * @param {String} path
+ * @param {Boolean?} hardened
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.isValidPath = function isValidPath(path) {
+  if (typeof path !== 'string')
+    return false;
+
+  try {
+    HD.parsePath(path, constants.hd.MAX_INDEX);
+    return true;
+  } catch (e) {
+    return false;
+  }
+};
+
+/**
+ * Derive a key from a derivation path.
+ * @param {String} path
+ * @returns {HDPrivateKey}
+ * @throws Error if `path` is not a valid path.
+ */
+
+HDPrivateKey.prototype.derivePath = function derivePath(path) {
+  var indexes = HD.parsePath(path, constants.hd.MAX_INDEX);
+  var key = this;
+  var i;
+
+  for (i = 0; i < indexes.length; i++)
+    key = key.derive(indexes[i]);
+
+  return key;
+};
+
+/**
+ * Compare a key against an object.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.prototype.equal = function equal(obj) {
+  if (!HDPrivateKey.isHDPrivateKey(obj))
+    return false;
+
+  return this.network === obj.network
+    && this.depth === obj.depth
+    && utils.equal(this.parentFingerPrint, obj.parentFingerPrint)
+    && this.childIndex === obj.childIndex
+    && utils.equal(this.chainCode, obj.chainCode)
+    && utils.equal(this.privateKey, obj.privateKey);
+};
+
+/**
+ * Compare a key against an object.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.prototype.compare = function compare(key) {
+  var cmp;
+
+  if (!HDPrivateKey.isHDPrivateKey(key))
+    return 1;
+
+  cmp = this.depth - key.depth;
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.parentFingerPrint, key.parentFingerPrint);
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = this.childIndex - key.childIndex;
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.chainCode, key.chainCode);
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.privateKey, key.privateKey);
+
+  if (cmp !== 0)
+    return cmp;
+
+  return 0;
+};
+
+/**
+ * Inject properties from seed.
+ * @private
+ * @param {Buffer} seed
+ * @param {(Network|NetworkType)?} network
+ */
+
+HDPrivateKey.prototype.fromSeed = function fromSeed(seed, network) {
+  var hash, left, right;
+
+  assert(Buffer.isBuffer(seed));
+
+  if (!(seed.length * 8 >= constants.hd.MIN_ENTROPY
+      && seed.length * 8 <= constants.hd.MAX_ENTROPY)) {
+    throw new Error('Entropy not in range.');
+  }
+
+  hash = utils.hmac('sha512', seed, 'Bitcoin seed');
+
+  left = hash.slice(0, 32);
+  right = hash.slice(32, 64);
+
+  // Only a 1 in 2^127 chance of happening.
+  if (!ec.privateKeyVerify(left))
+    throw new Error('Master private key is invalid.');
+
+  this.network = bcoin.network.get(network);
+  this.depth = 0;
+  this.parentFingerPrint = new Buffer([0, 0, 0, 0]);
+  this.childIndex = 0;
+  this.chainCode = right;
+  this.privateKey = left;
+  this.publicKey = ec.publicKeyCreate(left, true);
+
+  return this;
+};
+
+/**
+ * Instantiate an hd private key from a 512 bit seed.
+ * @param {Buffer} seed
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromSeed = function fromSeed(seed, network) {
+  return new HDPrivateKey().fromSeed(seed, network);
+};
+
+/**
+ * Inject properties from a mnemonic.
+ * @private
+ * @param {Mnemonic|Object} mnemonic
+ * @param {(Network|NetworkType)?} network
+ */
+
+HDPrivateKey.prototype.fromMnemonic = function fromMnemonic(mnemonic, network) {
+  if (!(mnemonic instanceof HD.Mnemonic))
+    mnemonic = new HD.Mnemonic(mnemonic);
+  this.fromSeed(mnemonic.toSeed(), network);
+  this.mnemonic = mnemonic;
+  return this;
+};
+
+/**
+ * Instantiate an hd private key from a mnemonic.
+ * @param {Mnemonic|Object} mnemonic
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromMnemonic = function fromMnemonic(mnemonic, network) {
+  return new HDPrivateKey().fromMnemonic(mnemonic, network);
+};
+
+/**
+ * Inject properties from privateKey and entropy.
+ * @private
+ * @param {Buffer} key
+ * @param {Buffer} entropy
+ * @param {(Network|NetworkType)?} network
+ */
+
+HDPrivateKey.prototype.fromKey = function fromKey(key, entropy, network) {
+  assert(Buffer.isBuffer(key) && key.length === 32);
+  assert(Buffer.isBuffer(entropy) && entropy.length === 32);
+  this.network = bcoin.network.get(network);
+  this.depth = 0;
+  this.parentFingerPrint = new Buffer([0, 0, 0, 0]);
+  this.childIndex = 0;
+  this.chainCode = entropy;
+  this.privateKey = key;
+  this.publicKey = ec.publicKeyCreate(key, true);
+  return this;
+};
+
+/**
+ * Create an hd private key from a key and entropy bytes.
+ * @param {Buffer} key
+ * @param {Buffer} entropy
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromKey = function fromKey(key, entropy, network) {
+  return new HDPrivateKey().fromKey(key, entropy, network);
+};
+
+/**
+ * Generate an hd private key.
+ * @param {(Network|NetworkType)?} network
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.generate = function generate(network) {
+  var key = ec.generatePrivateKey();
+  var entropy = ec.random(32);
+  return HDPrivateKey.fromKey(key, entropy, network);
+};
+
+/**
+ * Inject properties from base58 key.
+ * @private
+ * @param {Base58String} xkey
+ */
+
+HDPrivateKey.prototype.fromBase58 = function fromBase58(xkey) {
+  this.fromRaw(utils.fromBase58(xkey));
+  this._xprivkey = xkey;
+  return this;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} raw
+ */
+
+HDPrivateKey.prototype.fromRaw = function fromRaw(raw) {
+  var p = new BufferReader(raw);
+  var i, version, type, prefix;
+
+  version = p.readU32BE();
+  this.depth = p.readU8();
+  this.parentFingerPrint = p.readBytes(4);
+  this.childIndex = p.readU32BE();
+  this.chainCode = p.readBytes(32);
+  p.readU8();
+  this.privateKey = p.readBytes(32);
+  p.verifyChecksum();
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xprivkey;
+    if (version === prefix)
+      break;
+  }
+
+  assert(i < networks.types.length, 'Network not found.');
+
+  this.publicKey = ec.publicKeyCreate(this.privateKey, true);
+  this.network = bcoin.network.get(type);
+
+  return this;
+};
+
+/**
+ * Serialize key to a base58 string.
+ * @param {(Network|NetworkType)?} network
+ * @returns {Base58String}
+ */
+
+HDPrivateKey.prototype.toBase58 = function toBase58(network) {
+  return utils.toBase58(this.toRaw(network));
+};
+
+/**
+ * Serialize the key.
+ * @param {(Network|NetworkType)?} network
+ * @returns {Buffer}
+ */
+
+HDPrivateKey.prototype.toRaw = function toRaw(network, writer) {
+  var p = new BufferWriter(writer);
+
+  if (!network)
+    network = this.network;
+
+  network = bcoin.network.get(network);
+
+  p.writeU32BE(network.keyPrefix.xprivkey);
+  p.writeU8(this.depth);
+  p.writeBytes(this.parentFingerPrint);
+  p.writeU32BE(this.childIndex);
+  p.writeBytes(this.chainCode);
+  p.writeU8(0);
+  p.writeBytes(this.privateKey);
+  p.writeChecksum();
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Serialize the key in "extended"
+ * format (includes the mnemonic).
+ * @param {(Network|NetworkType)?} network
+ * @returns {Buffer}
+ */
+
+HDPrivateKey.prototype.toExtended = function toExtended(network, writer) {
+  var p = new BufferWriter(writer);
+
+  this.toRaw(network, p);
+
+  if (this.mnemonic) {
+    p.writeU8(1);
+    this.mnemonic.toRaw(p);
+  } else {
+    p.writeU8(0);
+  }
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from extended serialized data.
+ * @private
+ * @param {Buffer} data
+ */
+
+HDPrivateKey.prototype.fromExtended = function fromExtended(data) {
+  var p = new BufferReader(data);
+  this.fromRaw(p);
+  if (p.readU8() === 1)
+    this.mnemonic = HD.Mnemonic.fromRaw(p);
+  return this;
+};
+
+/**
+ * Instantiate key from "extended" serialized data.
+ * @param {Buffer} data
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromExtended = function fromExtended(data) {
+  return new HDPrivateKey().fromExtended(data);
+};
+
+/**
+ * Instantiate an HD private key from a base58 string.
+ * @param {Base58String} xkey
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromBase58 = function fromBase58(xkey) {
+  return new HDPrivateKey().fromBase58(xkey);
+};
+
+/**
+ * Instantiate key from serialized data.
+ * @param {Buffer} raw
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromRaw = function fromRaw(raw) {
+  return new HDPrivateKey().fromRaw(raw);
+};
+
+/**
+ * Convert key to a more json-friendly object.
+ * @returns {Object}
+ */
+
+HDPrivateKey.prototype.toJSON = function toJSON() {
+  return {
+    xprivkey: this.xprivkey,
+    mnemonic: this.mnemonic ? this.mnemonic.toJSON() : null
+  };
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {Object} json
+ */
+
+HDPrivateKey.prototype.fromJSON = function fromJSON(json) {
+  assert(json.xprivkey, 'Could not handle key JSON.');
+
+  this.fromBase58(json.xprivkey);
+
+  if (json.mnemonic)
+    this.mnemonic = HD.Mnemonic.fromJSON(json.mnemonic);
+
+  return this;
+};
+
+/**
+ * Instantiate an HDPrivateKey from a jsonified key object.
+ * @param {Object} json - The jsonified key object.
+ * @returns {HDPrivateKey}
+ */
+
+HDPrivateKey.fromJSON = function fromJSON(json) {
+  return new HDPrivateKey().fromJSON(json);
+};
+
+/**
+ * Test whether an object is an HDPrivateKey.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPrivateKey.isHDPrivateKey = function isHDPrivateKey(obj) {
+  return obj
+    && typeof obj.derive === 'function'
+    && typeof obj.toExtended === 'function'
+    && obj.chainCode !== undefined;
+};
+
+/*
+ * Expose
+ */
+
+module.exports = HDPrivateKey;
diff --git a/lib/bcoin/hd/public.js b/lib/bcoin/hd/public.js
new file mode 100644
index 00000000..d0848309
--- /dev/null
+++ b/lib/bcoin/hd/public.js
@@ -0,0 +1,557 @@
+/*!
+ * public.js - hd public keys for bcoin
+ * Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var ec = require('../crypto/ec');
+var assert = utils.assert;
+var constants = bcoin.constants;
+var networks = bcoin.networks;
+var BufferWriter = require('../utils/writer');
+var BufferReader = require('../utils/reader');
+var HD = require('./hd');
+
+/*
+ * Constants
+ */
+
+var FINGER_PRINT = new Buffer('00000000', 'hex');
+
+/**
+ * HDPublicKey
+ * @exports HDPublicKey
+ * @constructor
+ * @param {Object|Base58String} options
+ * @param {Base58String?} options.xkey - Serialized base58 key.
+ * @param {Number?} options.depth
+ * @param {Buffer?} options.parentFingerPrint
+ * @param {Number?} options.childIndex
+ * @param {Buffer?} options.chainCode
+ * @param {Buffer?} options.publicKey
+ * @property {Network} network
+ * @property {Base58String} xpubkey
+ * @property {Number} depth
+ * @property {Buffer} parentFingerPrint
+ * @property {Number} childIndex
+ * @property {Buffer} chainCode
+ * @property {Buffer} publicKey
+ */
+
+function HDPublicKey(options) {
+  if (!(this instanceof HDPublicKey))
+    return new HDPublicKey(options);
+
+  this.network = bcoin.network.get();
+  this.depth = 0;
+  this.parentFingerPrint = FINGER_PRINT;
+  this.childIndex = 0;
+  this.chainCode = constants.ZERO_HASH;
+  this.publicKey = constants.ZERO_KEY;
+
+  this.fingerPrint = null;
+
+  this._xpubkey = null;
+
+  this.hdPublicKey = this;
+  this.hdPrivateKey = null;
+
+  if (options)
+    this.fromOptions(options);
+}
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+HDPublicKey.prototype.fromOptions = function fromOptions(options) {
+  assert(options, 'No options for HDPublicKey');
+  assert(utils.isNumber(options.depth));
+  assert(Buffer.isBuffer(options.parentFingerPrint));
+  assert(utils.isNumber(options.childIndex));
+  assert(Buffer.isBuffer(options.chainCode));
+  assert(Buffer.isBuffer(options.publicKey));
+
+  if (options.network)
+    this.network = bcoin.network.get(options.network);
+
+  this.depth = options.depth;
+  this.parentFingerPrint = options.parentFingerPrint;
+  this.childIndex = options.childIndex;
+  this.chainCode = options.chainCode;
+  this.publicKey = options.publicKey;
+
+  if (options.xpubkey) {
+    assert(typeof options.xpubkey === 'string');
+    this._xpubkey = options.xpubkey;
+  }
+
+  return this;
+};
+
+/**
+ * Instantiate HD public key from options object.
+ * @param {Object} options
+ * @returns {HDPublicKey}
+ */
+
+HDPublicKey.fromOptions = function fromOptions(options) {
+  return new HDPublicKey().fromOptions(options);
+};
+
+HDPublicKey.prototype.__defineGetter__('xpubkey', function() {
+  if (!this._xpubkey)
+    this._xpubkey = this.toBase58();
+  return this._xpubkey;
+});
+
+/**
+ * Destroy the key (zeroes chain code and pubkey).
+ */
+
+HDPublicKey.prototype.destroy = function destroy() {
+  this.depth = 0;
+  this.parentFingerPrint.fill(0);
+  this.childIndex = 0;
+  this.chainCode.fill(0);
+  this.publicKey.fill(0);
+
+  if (this.fingerPrint) {
+    this.fingerPrint.fill(0);
+    this.fingerPrint = null;
+  }
+
+  this._xpubkey = null;
+};
+
+/**
+ * Derive a child key.
+ * @param {Number|String} - Child index or path.
+ * @param {Boolean?} hardened - Whether the derivation
+ * should be hardened (throws if true).
+ * @returns {HDPrivateKey}
+ * @throws on `hardened`
+ */
+
+HDPublicKey.prototype.derive = function derive(index, hardened) {
+  var p, id, data, hash, left, right, key, child;
+
+  if (typeof index === 'string')
+    return this.derivePath(index);
+
+  if (index >= constants.hd.HARDENED || hardened)
+    throw new Error('Index out of range.');
+
+  if (index < 0)
+    throw new Error('Index out of range.');
+
+  if (this.depth >= 0xff)
+    throw new Error('Depth too high.');
+
+  id = this.getID(index);
+  child = HD.cache.get(id);
+
+  if (child)
+    return child;
+
+  p = new BufferWriter();
+  p.writeBytes(this.publicKey);
+  p.writeU32BE(index);
+  data = p.render();
+
+  hash = utils.hmac('sha512', data, this.chainCode);
+  left = hash.slice(0, 32);
+  right = hash.slice(32, 64);
+
+  try {
+    key = ec.publicKeyTweakAdd(this.publicKey, left, true);
+  } catch (e) {
+    return this.derive(index + 1);
+  }
+
+  if (!this.fingerPrint)
+    this.fingerPrint = utils.hash160(this.publicKey).slice(0, 4);
+
+  child = new HDPublicKey();
+  child.network = this.network;
+  child.depth = this.depth + 1;
+  child.parentFingerPrint = this.fingerPrint;
+  child.childIndex = index;
+  child.chainCode = right;
+  child.publicKey = key;
+
+  HD.cache.set(id, child);
+
+  return child;
+};
+
+/**
+ * Unique HD key ID.
+ * @private
+ * @param {Number} index
+ * @returns {String}
+ */
+
+HDPublicKey.prototype.getID = function getID(index) {
+  return this.network.keyPrefix.xpubkey58
+    + this.publicKey.toString('hex')
+    + index;
+};
+
+/**
+ * Derive a BIP44 account key (does not derive, only ensures account key).
+ * @method
+ * @param {Number} accountIndex
+ * @returns {HDPublicKey}
+ * @throws Error if key is not already an account key.
+ */
+
+HDPublicKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex) {
+  assert(this.isAccount44(accountIndex), 'Cannot derive account index.');
+  return this;
+};
+
+/**
+ * Derive a BIP45 purpose key (does not derive, only ensures account key).
+ * @method
+ * @returns {HDPublicKey}
+ * @throws Error if key is not already a purpose key.
+ */
+
+HDPublicKey.prototype.derivePurpose45 = function derivePurpose45() {
+  assert(this.isPurpose45(), 'Cannot derive purpose 45.');
+  return this;
+};
+
+/**
+ * Test whether the key is a master key.
+ * @method
+ * @returns {Boolean}
+ */
+
+HDPublicKey.prototype.isMaster = function() {
+  return HD.PrivateKey.prototype.isMaster.call(this);
+};
+
+/**
+ * Test whether the key is (most likely) a BIP44 account key.
+ * @method
+ * @param {Number?} accountIndex
+ * @returns {Boolean}
+ */
+
+HDPublicKey.prototype.isAccount44 = function(accountIndex) {
+  return HD.PrivateKey.prototype.isAccount44.call(this, accountIndex);
+};
+
+/**
+ * Test whether the key is a BIP45 purpose key.
+ * @method
+ * @returns {Boolean}
+ */
+
+HDPublicKey.prototype.isPurpose45 = function() {
+  return HD.PrivateKey.prototype.isPurpose45.call(this);
+};
+
+/**
+ * Test whether a string is a valid path.
+ * @param {String} path
+ * @param {Boolean?} hardened
+ * @returns {Boolean}
+ */
+
+HDPublicKey.isValidPath = function isValidPath(path) {
+  if (typeof path !== 'string')
+    return false;
+
+  try {
+    HD.parsePath(path, constants.hd.HARDENED);
+    return true;
+  } catch (e) {
+    return false;
+  }
+};
+
+/**
+ * Derive a key from a derivation path.
+ * @param {String} path
+ * @returns {HDPublicKey}
+ * @throws Error if `path` is not a valid path.
+ * @throws Error if hardened.
+ */
+
+HDPublicKey.prototype.derivePath = function derivePath(path) {
+  var indexes = HD.parsePath(path, constants.hd.HARDENED);
+  var key = this;
+  var i;
+
+  for (i = 0; i < indexes.length; i++)
+    key = key.derive(indexes[i]);
+
+  return key;
+};
+
+/**
+ * Compare a key against an object.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPublicKey.prototype.equal = function equal(obj) {
+  if (!HDPublicKey.isHDPublicKey(obj))
+    return false;
+
+  return this.network === obj.network
+    && this.depth === obj.depth
+    && utils.equal(this.parentFingerPrint, obj.parentFingerPrint)
+    && this.childIndex === obj.childIndex
+    && utils.equal(this.chainCode, obj.chainCode)
+    && utils.equal(this.publicKey, obj.publicKey);
+};
+
+/**
+ * Compare a key against an object.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPublicKey.prototype.compare = function compare(key) {
+  var cmp;
+
+  if (!HDPublicKey.isHDPublicKey(key))
+    return 1;
+
+  cmp = this.depth - key.depth;
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.parentFingerPrint, key.parentFingerPrint);
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = this.childIndex - key.childIndex;
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.chainCode, key.chainCode);
+
+  if (cmp !== 0)
+    return cmp;
+
+  cmp = utils.cmp(this.publicKey, key.publicKey);
+
+  if (cmp !== 0)
+    return cmp;
+
+  return 0;
+};
+
+/**
+ * Convert key to a more json-friendly object.
+ * @returns {Object}
+ */
+
+HDPublicKey.prototype.toJSON = function toJSON() {
+  return {
+    xpubkey: this.xpubkey
+  };
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {Object} json
+ */
+
+HDPublicKey.prototype.fromJSON = function fromJSON(json) {
+  assert(json.xpubkey, 'Could not handle HD key JSON.');
+  this.fromBase58(json.xpubkey);
+  return this;
+};
+
+/**
+ * Instantiate an HDPrivateKey from a jsonified key object.
+ * @param {Object} json - The jsonified transaction object.
+ * @returns {HDPrivateKey}
+ */
+
+HDPublicKey.fromJSON = function fromJSON(json) {
+  return new HDPublicKey().fromJSON(json);
+};
+
+/**
+ * Test whether an object is in the form of a base58 xpubkey.
+ * @param {String} data
+ * @returns {Boolean}
+ */
+
+HDPublicKey.isExtended = function isExtended(data) {
+  var i, type, prefix;
+
+  if (typeof data !== 'string')
+    return false;
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xpubkey58;
+    if (data.indexOf(prefix) === 0)
+      return true;
+  }
+
+  return false;
+};
+
+/**
+ * Test whether a buffer has a valid network prefix.
+ * @param {Buffer} data
+ * @returns {NetworkType}
+ */
+
+HDPublicKey.hasPrefix = function hasPrefix(data) {
+  var i, version, prefix, type;
+
+  if (!Buffer.isBuffer(data))
+    return false;
+
+  version = data.readUInt32BE(0, true);
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xpubkey;
+    if (version === prefix)
+      return type;
+  }
+
+  return false;
+};
+
+/**
+ * Inject properties from a base58 key.
+ * @private
+ * @param {Base58String} xkey
+ */
+
+HDPublicKey.prototype.fromBase58 = function fromBase58(xkey) {
+  this.fromRaw(utils.fromBase58(xkey));
+  this._xpubkey = xkey;
+  return this;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} raw
+ */
+
+HDPublicKey.prototype.fromRaw = function fromRaw(raw) {
+  var p = new BufferReader(raw);
+  var i, version, type, prefix;
+
+  version = p.readU32BE();
+  this.depth = p.readU8();
+  this.parentFingerPrint = p.readBytes(4);
+  this.childIndex = p.readU32BE();
+  this.chainCode = p.readBytes(32);
+  this.publicKey = p.readBytes(33);
+  p.verifyChecksum();
+
+  for (i = 0; i < networks.types.length; i++) {
+    type = networks.types[i];
+    prefix = networks[type].keyPrefix.xpubkey;
+    if (version === prefix)
+      break;
+  }
+
+  assert(i < networks.types.length, 'Network not found.');
+
+  this.network = bcoin.network.get(type);
+
+  return this;
+};
+
+/**
+ * Serialize key data to base58 extended key.
+ * @param {Network|String} network
+ * @returns {Base58String}
+ */
+
+HDPublicKey.prototype.toBase58 = function toBase58(network) {
+  return utils.toBase58(this.toRaw(network));
+};
+
+/**
+ * Serialize the key.
+ * @param {Network|NetworkType} network
+ * @returns {Buffer}
+ */
+
+HDPublicKey.prototype.toRaw = function toRaw(network, writer) {
+  var p = new BufferWriter(writer);
+
+  if (!network)
+    network = this.network;
+
+  network = bcoin.network.get(network);
+
+  p.writeU32BE(network.keyPrefix.xpubkey);
+  p.writeU8(this.depth);
+  p.writeBytes(this.parentFingerPrint);
+  p.writeU32BE(this.childIndex);
+  p.writeBytes(this.chainCode);
+  p.writeBytes(this.publicKey);
+  p.writeChecksum();
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Instantiate an HD public key from a base58 string.
+ * @param {Base58String} xkey
+ * @returns {HDPublicKey}
+ */
+
+HDPublicKey.fromBase58 = function fromBase58(xkey) {
+  return new HDPublicKey().fromBase58(xkey);
+};
+
+/**
+ * Instantiate key from serialized data.
+ * @param {Buffer} raw
+ * @returns {HDPublicKey}
+ */
+
+HDPublicKey.fromRaw = function fromRaw(data) {
+  return new HDPublicKey().fromRaw(data);
+};
+
+/**
+ * Test whether an object is a HDPublicKey.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+HDPublicKey.isHDPublicKey = function isHDPublicKey(obj) {
+  return obj
+    && typeof obj.derive === 'function'
+    && typeof obj.toExtended !== 'function'
+    && obj.chainCode !== undefined;
+};
+
+/*
+ * Expose
+ */
+
+module.exports = HDPublicKey;
diff --git a/lib/bcoin/net/packets.js b/lib/bcoin/net/packets.js
index a391c82b..0b0924b0 100644
--- a/lib/bcoin/net/packets.js
+++ b/lib/bcoin/net/packets.js
@@ -236,106 +236,6 @@ VersionPacket.fromRaw = function fromRaw(data, enc) {
   return new VersionPacket().fromRaw(data, enc);
 };
 
-/**
- * Inv Item
- * @param {Number} type
- * @param {Hash} hash
- * @property {InvType} type
- * @property {Hash} hash
- */
-
-function InvItem(type, hash) {
-  if (!(this instanceof InvItem))
-    return new InvItem(type, hash);
-
-  this.type = type;
-  this.hash = hash;
-}
-
-/**
- * Serialize inv item.
- * @returns {Buffer}
- */
-
-InvItem.prototype.toRaw = function toRaw(writer) {
-  var p = bcoin.writer(writer);
-
-  p.writeU32(this.type);
-  p.writeHash(this.hash);
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from serialized data.
- * @param {Buffer} data
- */
-
-InvItem.prototype.fromRaw = function fromRaw(data) {
-  var p = bcoin.reader(data);
-  this.type = p.readU32();
-  this.hash = p.readHash('hex');
-  return this;
-};
-
-/**
- * Instantiate inv item from serialized data.
- * @param {Buffer} data
- * @param {String?} enc
- * @returns {InvItem}
- */
-
-InvItem.fromRaw = function fromRaw(data, enc) {
-  if (typeof data === 'string')
-    data = new Buffer(data, enc);
-  return new InvItem().fromRaw(data);
-};
-
-/**
- * Test whether the inv item is a block.
- * @returns {Boolean}
- */
-
-InvItem.prototype.isBlock = function isBlock() {
-  switch (this.type) {
-    case constants.inv.BLOCK:
-    case constants.inv.WITNESS_BLOCK:
-    case constants.inv.FILTERED_BLOCK:
-    case constants.inv.WITNESS_FILTERED_BLOCK:
-    case constants.inv.CMPCT_BLOCK:
-      return true;
-    default:
-      return false;
-  }
-};
-
-/**
- * Test whether the inv item is a tx.
- * @returns {Boolean}
- */
-
-InvItem.prototype.isTX = function isTX() {
-  switch (this.type) {
-    case constants.inv.TX:
-    case constants.inv.WITNESS_TX:
-      return true;
-    default:
-      return false;
-  }
-};
-
-/**
- * Test whether the inv item has the witness bit set.
- * @returns {Boolean}
- */
-
-InvItem.prototype.hasWitness = function hasWitness() {
-  return (this.type & constants.WITNESS_MASK) !== 0;
-};
-
 /**
  * Represents a `getblocks` packet.
  * @exports GetBlocksPacket
@@ -1102,7 +1002,6 @@ NetworkAddress.prototype.toRaw = function toRaw(full, writer) {
  */
 
 exports.VersionPacket = VersionPacket;
-exports.InvItem = InvItem;
 exports.GetBlocksPacket = GetBlocksPacket;
 exports.AlertPacket = AlertPacket;
 exports.RejectPacket = RejectPacket;
diff --git a/lib/bcoin/net/parser.js b/lib/bcoin/net/parser.js
index 62dcbc29..82e4dfff 100644
--- a/lib/bcoin/net/parser.js
+++ b/lib/bcoin/net/parser.js
@@ -568,7 +568,7 @@ Parser.parseInv = function parseInv(p) {
   assert(count <= 50000, 'Item count too high.');
 
   for (i = 0; i < count; i++)
-    items.push(bcoin.packets.InvItem.fromRaw(p));
+    items.push(bcoin.invitem.fromRaw(p));
 
   return items;
 };
diff --git a/lib/bcoin/net/peer.js b/lib/bcoin/net/peer.js
index a71517ff..ba244185 100644
--- a/lib/bcoin/net/peer.js
+++ b/lib/bcoin/net/peer.js
@@ -15,7 +15,7 @@ var Parser = require('./parser');
 var Framer = require('./framer');
 var assert = utils.assert;
 var constants = bcoin.constants;
-var InvItem = bcoin.packets.InvItem;
+var InvItem = bcoin.invitem;
 var VersionPacket = bcoin.packets.VersionPacket;
 var GetBlocksPacket = bcoin.packets.GetBlocksPacket;
 var RejectPacket = bcoin.packets.RejectPacket;
diff --git a/lib/bcoin/net/pool.js b/lib/bcoin/net/pool.js
index 63e90741..26f1f0e5 100644
--- a/lib/bcoin/net/pool.js
+++ b/lib/bcoin/net/pool.js
@@ -16,7 +16,7 @@ var assert = utils.assert;
 var constants = bcoin.constants;
 var VerifyError = bcoin.errors.VerifyError;
 var NetworkAddress = bcoin.packets.NetworkAddress;
-var InvItem = bcoin.packets.InvItem;
+var InvItem = bcoin.invitem;
 
 /**
  * A pool of peers for handling all network activity.
diff --git a/lib/bcoin/primitives/hd.js b/lib/bcoin/primitives/hd.js
deleted file mode 100644
index 6c45695b..00000000
--- a/lib/bcoin/primitives/hd.js
+++ /dev/null
@@ -1,2230 +0,0 @@
-/*!
- * @module hd
- *
- * @description
- * HD mnemonics and keys (BIP32, BIP39) for bcoin.
- * Code adapted from bitcore-lib:
- * - {@link https://github.com/bitpay/bitcore-lib/blob/master/lib/hdprivatekey.js}
- * - {@link https://github.com/bitpay/bitcore-lib/blob/master/lib/hdpublickey.js}
- * - {@link https://github.com/ryanxcharles/fullnode/blob/master/lib/bip32.js}
- * - {@link https://github.com/bitpay/bitcore-mnemonic/blob/master/lib/mnemonic.js}
- *
- * @see https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
- * @see https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
- *
- * @license
- *
- * BIP32
- * Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
- * https://github.com/bcoin-org/bcoin
- *
- * Copyright (c) 2013-2015 BitPay, Inc.
- *
- * Parts of this software are based on Bitcoin Core
- * Copyright (c) 2009-2015 The Bitcoin Core developers
- *
- * Parts of this software are based on fullnode
- * Copyright (c) 2014 Ryan X. Charles
- * Copyright (c) 2014 reddit, Inc.
- *
- * Parts of this software are based on BitcoinJS
- * Copyright (c) 2011 Stefan Thomas <justmoon@members.fsf.org>
- *
- * Parts of this software are based on BitcoinJ
- * Copyright (c) 2011 Google Inc.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- * BIP39
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2014 BitPay
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-'use strict';
-
-var bcoin = require('../env');
-var utils = require('../utils/utils');
-var ec = require('../crypto/ec');
-var assert = utils.assert;
-var constants = bcoin.constants;
-var networks = bcoin.networks;
-var KeyRing = bcoin.keyring;
-var LRU = require('../utils/lru');
-var BufferWriter = require('../utils/writer');
-var BufferReader = require('../utils/reader');
-var unorm;
-
-/*
- * Constants
- */
-
-var FINGER_PRINT = new Buffer('00000000', 'hex');
-
-/**
- * HD Mnemonic
- * @exports Mnemonic
- * @constructor
- * @param {Object} options
- * @param {Number?} options.bit - Bits of entropy (Must
- * be a multiple of 8) (default=128).
- * @param {Buffer?} options.entropy - Entropy bytes. Will
- * be generated with `options.bits` bits of entropy
- * if not present.
- * @param {String?} options.phrase - Mnemonic phrase (will
- * be generated if not present).
- * @param {String?} options.passphrase - Optional salt for
- * key stretching (empty string if not present).
- * @param {String?} options.language - Language.
- */
-
-function Mnemonic(options) {
-  if (!(this instanceof Mnemonic))
-    return new Mnemonic(options);
-
-  this.bits = constants.hd.MIN_ENTROPY;
-  this.language = 'english';
-  this.entropy = null;
-  this.phrase = null;
-  this.passphrase = '';
-
-  if (options)
-    this.fromOptions(options);
-}
-
-/**
- * List of languages.
- * @const {String[]}
- * @default
- */
-
-Mnemonic.languages = [
-  'simplified chinese',
-  'traditional chinese',
-  'english',
-  'french',
-  'italian',
-  'japanese'
-];
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-Mnemonic.prototype.fromOptions = function fromOptions(options) {
-  if (typeof options === 'string')
-    options = { phrase: options };
-
-  if (options.bits != null) {
-    assert(utils.isNumber(options.bits));
-    assert(options.bits >= constants.hd.MIN_ENTROPY);
-    assert(options.bits <= constants.hd.MAX_ENTROPY);
-    assert(options.bits % 32 === 0);
-    this.bits = options.bits;
-  }
-
-  if (options.language) {
-    assert(typeof options.language === 'string');
-    assert(Mnemonic.languages.indexOf(options.language) !== -1);
-    this.language = options.language;
-  }
-
-  if (options.passphrase) {
-    assert(typeof options.passphrase === 'string');
-    this.passphrase = options.passphrase;
-  }
-
-  if (options.phrase) {
-    this.fromPhrase(options.phrase);
-    return this;
-  }
-
-  if (options.entropy) {
-    this.fromEntropy(options.entropy);
-    return this;
-  }
-
-  return this;
-};
-
-/**
- * Instantiate mnemonic from options.
- * @param {Object} options
- * @returns {Mnemonic}
- */
-
-Mnemonic.fromOptions = function fromOptions(options) {
-  return new Mnemonic().fromOptions(options);
-};
-
-/**
- * Destroy the mnemonic (zeroes entropy).
- */
-
-Mnemonic.prototype.destroy = function destroy() {
-  this.bits = constants.hd.MIN_ENTROPY;
-  this.language = 'english';
-  if (this.entropy) {
-    this.entropy.fill(0);
-    this.entropy = null;
-  }
-  this.phrase = null;
-  this.passphrase = '';
-};
-
-/**
- * Generate the seed.
- * @param {String?} passphrase
- * @returns {Buffer} pbkdf2 seed.
- */
-
-Mnemonic.prototype.toSeed = function toSeed(passphrase) {
-  if (!passphrase)
-    passphrase = this.passphrase;
-
-  this.passphrase = passphrase;
-
-  return utils.pbkdf2Sync(
-    nfkd(this.getPhrase()),
-    nfkd('mnemonic' + passphrase),
-    2048, 64, 'sha512');
-};
-
-/**
- * Generate seed and create an hd private key.
- * @param {String?} passphrase
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey}
- */
-
-Mnemonic.prototype.toKey = function toKey(passphrase, network) {
-  var seed = this.toSeed(passphrase);
-  var key = HDPrivateKey.fromSeed(seed, network);
-  key.mnemonic = this;
-  return key;
-};
-
-/**
- * Get or generate entropy.
- * @returns {Buffer}
- */
-
-Mnemonic.prototype.getEntropy = function getEntropy() {
-  if (!this.entropy)
-    this.entropy = ec.random(this.bits / 8);
-
-  assert(this.bits / 8 === this.entropy.length);
-
-  return this.entropy;
-};
-
-/**
- * Generate a mnemonic phrase from chosen language.
- * @returns {String}
- */
-
-Mnemonic.prototype.getPhrase = function getPhrase() {
-  var i, j, phrase, wordlist, bits, entropy, index, pos, oct, bit;
-
-  if (this.phrase)
-    return this.phrase;
-
-  phrase = [];
-  wordlist = Mnemonic.getWordlist(this.language);
-
-  entropy = this.getEntropy();
-  bits = this.bits;
-
-  // Append the hash to the entropy to
-  // make things easy when grabbing
-  // the checksum bits.
-  entropy = Buffer.concat([entropy, utils.sha256(entropy)]);
-
-  // Include the first `ENT / 32` bits
-  // of the hash (the checksum).
-  bits += bits / 32;
-
-  // Build the mnemonic by reading
-  // 11 bit indexes from the entropy.
-  for (i = 0; i < bits / 11; i++) {
-    index = 0;
-    for (j = 0; j < 11; j++) {
-      pos = i * 11 + j;
-      bit = pos % 8;
-      oct = (pos - bit) / 8;
-      index <<= 1;
-      index |= (entropy[oct] >>> (7 - bit)) & 1;
-    }
-    phrase.push(wordlist[index]);
-  }
-
-  // Japanese likes double-width spaces.
-  if (this.language === 'japanese')
-    phrase = phrase.join('\u3000');
-  else
-    phrase = phrase.join(' ');
-
-  this.phrase = phrase;
-
-  return phrase;
-};
-
-/**
- * Inject properties from phrase.
- * @private
- * @param {String} phrase
- */
-
-Mnemonic.prototype.fromPhrase = function fromPhrase(phrase) {
-  var i, j, bits, pos, oct, bit, b, ent, entropy, lang;
-  var chk, word, wordlist, index, cbits, cbytes, words;
-
-  assert(typeof phrase === 'string');
-
-  words = phrase.split(/[ \u3000]+/);
-  bits = words.length * 11;
-  cbits = bits % 32;
-  cbytes = Math.ceil(cbits / 8);
-  bits -= cbits;
-
-  assert(bits >= constants.hd.MIN_ENTROPY);
-  assert(bits <= constants.hd.MAX_ENTROPY);
-  assert(bits % 32 === 0);
-  assert(cbits !== 0, 'Invalid checksum.');
-
-  ent = new Buffer(Math.ceil((bits + cbits) / 8));
-  ent.fill(0);
-
-  lang = Mnemonic.getLanguage(words[0]);
-  wordlist = Mnemonic.getWordlist(lang);
-
-  for (i = 0; i < words.length; i++) {
-    word = words[i];
-    index = wordlist.indexOf(word);
-
-    if (index === -1)
-      throw new Error('Could not find word.');
-
-    for (j = 0; j < 11; j++) {
-      pos = i * 11 + j;
-      bit = pos % 8;
-      oct = (pos - bit) / 8;
-      b = (index >>> (10 - j)) & 1;
-      ent[oct] |= b << (7 - bit);
-    }
-  }
-
-  entropy = ent.slice(0, ent.length - cbytes);
-  ent = ent.slice(ent.length - cbytes);
-  chk = utils.sha256(entropy);
-
-  for (i = 0; i < cbits; i++) {
-    bit = i % 8;
-    oct = (i - bit) / 8;
-    b = (ent[oct] >>> (7 - bit)) & 1;
-    j = (chk[oct] >>> (7 - bit)) & 1;
-    if (b !== j)
-      throw new Error('Invalid checksum.');
-  }
-
-  assert(bits / 8 === entropy.length);
-
-  this.bits = bits;
-  this.language = lang;
-  this.entropy = entropy;
-  this.phrase = phrase;
-
-  return this;
-};
-
-/**
- * Instantiate mnemonic from a phrase (validates checksum).
- * @param {String} phrase
- * @returns {Mnemonic}
- * @throws on bad checksum
- */
-
-Mnemonic.fromPhrase = function fromPhrase(phrase) {
-  return new Mnemonic().fromPhrase(phrase);
-};
-
-/**
- * Inject properties from entropy.
- * @private
- * @param {Buffer} entropy
- * @param {String?} lang
- */
-
-Mnemonic.prototype.fromEntropy = function fromEntropy(entropy, lang) {
-  assert(Buffer.isBuffer(entropy));
-  assert(entropy.length * 8 >= constants.hd.MIN_ENTROPY);
-  assert(entropy.length * 8 <= constants.hd.MAX_ENTROPY);
-  assert((entropy.length * 8) % 32 === 0);
-  assert(!lang || Mnemonic.languages.indexOf(lang) !== -1);
-
-  this.entropy = entropy;
-  this.bits = entropy.length * 8;
-
-  if (lang)
-    this.language = lang;
-
-  return this;
-};
-
-/**
- * Instantiate mnemonic from entropy.
- * @param {Buffer} entropy
- * @param {String?} lang
- * @returns {Mnemonic}
- */
-
-Mnemonic.fromEntropy = function fromEntropy(entropy, lang) {
-  return new Mnemonic().fromEntropy(entropy, lang);
-};
-
-/**
- * Determine a single word's language.
- * @param {String} word
- * @returns {String} Language.
- * @throws on not found.
- */
-
-Mnemonic.getLanguage = function getLanguage(word) {
-  var i, lang, wordlist;
-
-  for (i = 0; i < Mnemonic.languages.length; i++) {
-    lang = Mnemonic.languages[i];
-    wordlist = Mnemonic.getWordlist(lang);
-    if (wordlist.indexOf(word) !== -1)
-      return lang;
-  }
-
-  throw new Error('Could not determine language.');
-};
-
-/**
- * Retrieve the wordlist for a language.
- * @param {String} language
- * @returns {String[]}
- */
-
-Mnemonic.getWordlist = function getWordlist(language) {
-  switch (language) {
-    case 'simplified chinese':
-      return require('../../../etc/chinese-simplified.js');
-    case 'traditional chinese':
-      return require('../../../etc/chinese-traditional.js');
-    case 'english':
-      return require('../../../etc/english.js');
-    case 'french':
-      return require('../../../etc/french.js');
-    case 'italian':
-      return require('../../../etc/italian.js');
-    case 'japanese':
-      return require('../../../etc/japanese.js');
-    default:
-      throw new Error('Unknown language: ' + language);
-  }
-};
-
-/**
- * Convert mnemonic to a json-friendly object.
- * @returns {Object}
- */
-
-Mnemonic.prototype.toJSON = function toJSON() {
-  return {
-    bits: this.bits,
-    language: this.language,
-    entropy: this.getEntropy().toString('hex'),
-    phrase: this.getPhrase(),
-    passphrase: this.passphrase
-  };
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {Object} json
- */
-
-Mnemonic.prototype.fromJSON = function fromJSON(json) {
-  assert(utils.isNumber(json.bits));
-  assert(typeof json.language === 'string');
-  assert(typeof json.entropy === 'string');
-  assert(typeof json.phrase === 'string');
-  assert(typeof json.passphrase === 'string');
-  assert(json.bits >= constants.hd.MIN_ENTROPY);
-  assert(json.bits <= constants.hd.MAX_ENTROPY);
-  assert(json.bits % 32 === 0);
-  assert(json.bits / 8 === json.entropy.length / 2);
-
-  this.bits = json.bits;
-  this.language = json.language;
-  this.entropy = new Buffer(json.entropy, 'hex');
-  this.phrase = json.phrase;
-  this.passphrase = json.passphrase;
-
-  return this;
-};
-
-/**
- * Instantiate mnemonic from json object.
- * @param {Object} json
- * @returns {Mnemonic}
- */
-
-Mnemonic.fromJSON = function fromJSON(json) {
-  return new Mnemonic().fromJSON(json);
-};
-
-/**
- * Serialize mnemonic.
- * @returns {Buffer}
- */
-
-Mnemonic.prototype.toRaw = function toRaw(writer) {
-  var p = new BufferWriter(writer);
-  var lang = Mnemonic.languages.indexOf(this.language);
-
-  assert(lang !== -1);
-
-  p.writeU16(this.bits);
-  p.writeU8(lang);
-  p.writeBytes(this.getEntropy());
-  p.writeVarString(this.getPhrase(), 'utf8');
-  p.writeVarString(this.passphrase, 'utf8');
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- */
-
-Mnemonic.prototype.fromRaw = function fromRaw(data) {
-  var p = new BufferReader(data);
-
-  this.bits = p.readU16();
-  this.language = Mnemonic.languages[p.readU8()];
-  this.entropy = p.readBytes(this.bits / 8);
-  this.phrase = p.readVarString('utf8');
-  this.passphrase = p.readVarString('utf8');
-
-  assert(this.language);
-  assert(this.bits >= constants.hd.MIN_ENTROPY);
-  assert(this.bits <= constants.hd.MAX_ENTROPY);
-  assert(this.bits % 32 === 0);
-
-  return this;
-};
-
-/**
- * Instantiate mnemonic from serialized data.
- * @param {Buffer} data
- * @returns {Mnemonic}
- */
-
-Mnemonic.fromRaw = function fromRaw(data) {
-  return new Mnemonic().fromRaw(data);
-};
-
-/**
- * Convert the mnemonic to a string.
- * @returns {String}
- */
-
-Mnemonic.prototype.toString = function toString() {
-  return this.getPhrase();
-};
-
-/**
- * Inspect the mnemonic.
- * @returns {String}
- */
-
-Mnemonic.prototype.inspect = function inspect() {
-  return '<Mnemonic: ' + this.getPhrase() + '>';
-};
-
-/**
- * Test whether an object is a Mnemonic.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-Mnemonic.isMnemonic = function isMnemonic(obj) {
-  return obj
-    && typeof obj.bits === 'number'
-    && typeof obj.toSeed === 'function';
-};
-
-/**
- * HD - Abstract class for HD keys. Will
- * potentially return an {@link HDPublicKey}
- * or {@link HDPrivateKey}.
- * @exports HD
- * @abstract
- * @constructor
- * @param {Object} options - {@link HDPublicKey}
- * or {@link HDPrivateKey} options.
- */
-
-function HD(options, network) {
-  if (!options)
-    return HD.fromMnemonic(null, network);
-  return HD.from(options, network);
-}
-
-/**
- * Instantiate an HD key (public or private) from an base58 string.
- * @param {Base58String} xkey
- * @returns {HDPrivateKey|HDPublicKey}
- */
-
-HD.fromBase58 = function fromBase58(xkey) {
-  if (HDPrivateKey.isExtended(xkey))
-    return HDPrivateKey.fromBase58(xkey);
-  return HDPublicKey.fromBase58(xkey);
-};
-
-/**
- * Generate an {@link HDPrivateKey}.
- * @param {Object} options
- * @param {Buffer?} options.privateKey
- * @param {Buffer?} options.entropy
- * @param {String?} network
- * @returns {HDPrivateKey}
- */
-
-HD.generate = function generate(options, network) {
-  return HDPrivateKey.generate(options, network);
-};
-
-/**
- * Generate an {@link HDPrivateKey} from a seed.
- * @param {Object|Mnemonic|Buffer} options - seed,
- * mnemonic, mnemonic options.
- * @param {String?} network
- * @returns {HDPrivateKey}
- */
-
-HD.fromSeed = function fromSeed(options, network) {
-  return HDPrivateKey.fromSeed(options, network);
-};
-
-/**
- * Instantiate an hd private key from a mnemonic.
- * @param {Mnemonic|Object} mnemonic
- * @param {String?} network
- * @returns {HDPrivateKey}
- */
-
-HD.fromMnemonic = function fromMnemonic(options, network) {
-  return HDPrivateKey.fromMnemonic(options, network);
-};
-
-/**
- * Instantiate an HD key from a jsonified key object.
- * @param {Object} json - The jsonified transaction object.
- * @returns {HDPrivateKey|HDPublicKey}
- */
-
-HD.fromJSON = function fromJSON(json) {
-  if (json.xprivkey)
-    return HDPrivateKey.fromJSON(json);
-  return HDPublicKey.fromJSON(json);
-};
-
-/**
- * Instantiate an HD key from serialized data.
- * @param {Buffer} data
- * @returns {HDPrivateKey|HDPublicKey}
- */
-
-HD.fromRaw = function fromRaw(data) {
-  if (HDPrivateKey.hasPrefix(data))
-    return HDPrivateKey.fromRaw(data);
-  return HDPublicKey.fromRaw(data);
-};
-
-/**
- * Instantiate HD key from extended serialized data.
- * @param {Buffer} data
- * @returns {HDPrivateKey|HDPublicKey}
- */
-
-HD.fromExtended = function fromExtended(data) {
-  if (HDPrivateKey.hasPrefix(data))
-    return HDPrivateKey.fromExtended(data);
-  return HDPublicKey.fromRaw(data);
-};
-
-/**
- * Generate an hdkey from any number of options.
- * @param {Object|Mnemonic|Buffer} options - mnemonic, mnemonic
- * options, seed, or base58 key.
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey|HDPublicKey}
- */
-
-HD.from = function from(options, network) {
-  var xkey;
-
-  assert(options, 'Options required.');
-
-  if (options.xkey)
-    xkey = options.xkey;
-  else if (options.xpubkey)
-    xkey = options.xpubkey;
-  else if (options.xprivkey)
-    xkey = options.xprivkey;
-  else
-    xkey = options;
-
-  if (HD.isExtended(xkey))
-    return HD.fromBase58(xkey);
-
-  if (HD.hasPrefix(options))
-    return HD.fromRaw(options);
-
-  return HD.fromMnemonic(options, network);
-};
-
-/**
- * Test whether an object is in the form of a base58 hd key.
- * @param {String} data
- * @returns {Boolean}
- */
-
-HD.isExtended = function isExtended(data) {
-  return HDPrivateKey.isExtended(data)
-    || HDPublicKey.isExtended(data);
-};
-
-/**
- * Test whether an object is in the form of a serialized hd key.
- * @param {Buffer} data
- * @returns {NetworkType}
- */
-
-HD.hasPrefix = function hasPrefix(data) {
-  return HDPrivateKey.hasPrefix(data)
-    || HDPublicKey.hasPrefix(data);
-};
-
-/**
- * Parse a derivation path and return an array of indexes.
- * @see https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
- * @param {String} path
- * @param {Number?} max - Max index.
- * @returns {Number[]}
- */
-
-HD.parsePath = function parsePath(path, max) {
-  var parts = path.split('/');
-  var root = parts.shift();
-  var result = [];
-  var i, hardened, index;
-
-  if (max == null)
-    max = constants.hd.MAX_INDEX;
-
-  if (root !== 'm'
-      && root !== 'M'
-      && root !== 'm\''
-      && root !== 'M\'') {
-    throw new Error('Bad path root.');
-  }
-
-  for (i = 0; i < parts.length; i++) {
-    index = parts[i];
-    hardened = index[index.length - 1] === '\'';
-
-    if (hardened)
-      index = index.slice(0, -1);
-
-    if (!/^\d+$/.test(index))
-      throw new Error('Non-number path index.');
-
-    index = parseInt(index, 10);
-
-    if (hardened)
-      index += constants.hd.HARDENED;
-
-    if (!(index >= 0 && index < max))
-      throw new Error('Index out of range.');
-
-    result.push(index);
-  }
-
-  return result;
-};
-
-/**
- * LRU cache to avoid deriving keys twice.
- * @type {LRU}
- */
-
-HD.cache = new LRU(500);
-
-/**
- * Test whether an object is an HD key.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HD.isHD = function isHD(obj) {
-  return HDPrivateKey.isHDPrivateKey(obj)
-    || HDPublicKey.isHDPublicKey(obj);
-};
-
-/**
- * Test whether an object is an HD private key.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HD.isPrivate = function isPrivate(obj) {
-  return HDPrivateKey.isHDPrivateKey(obj);
-};
-
-/**
- * Test whether an object is an HD public key.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HD.isPublic = function isPublic(obj) {
-  return HDPublicKey.isHDPublicKey(obj);
-};
-
-/**
- * HDPrivateKey
- * @exports HDPrivateKey
- * @constructor
- * @param {Object|Base58String} options
- * @param {Base58String?} options.xkey - Serialized base58 key.
- * @param {Mnemonic?} options.mnemonic
- * @param {Number?} options.depth
- * @param {Buffer?} options.parentFingerPrint
- * @param {Number?} options.childIndex
- * @param {Buffer?} options.chainCode
- * @param {Buffer?} options.privateKey
- * @property {Network} network
- * @property {Base58String} xprivkey
- * @property {Base58String} xpubkey
- * @property {Mnemonic?} mnemonic
- * @property {Number} depth
- * @property {Buffer} parentFingerPrint
- * @property {Number} childIndex
- * @property {Buffer} chainCode
- * @property {Buffer} privateKey
- * @property {HDPublicKey} hdPublicKey
- */
-
-function HDPrivateKey(options) {
-  if (!(this instanceof HDPrivateKey))
-    return new HDPrivateKey(options);
-
-  this.network = bcoin.network.get();
-  this.depth = 0;
-  this.parentFingerPrint = FINGER_PRINT;
-  this.childIndex = 0;
-  this.chainCode = constants.ZERO_HASH;
-  this.privateKey = constants.ZERO_HASH;
-
-  this.publicKey = constants.ZERO_KEY;
-  this.fingerPrint = null;
-
-  this.mnemonic = null;
-
-  this._xprivkey = null;
-
-  this.hdPrivateKey = this;
-  this._hdPublicKey = null;
-
-  if (options)
-    this.fromOptions(options);
-}
-
-utils.inherits(HDPrivateKey, HD);
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-HDPrivateKey.prototype.fromOptions = function fromOptions(options) {
-  assert(options, 'No options for HD private key.');
-  assert(utils.isNumber(options.depth));
-  assert(Buffer.isBuffer(options.parentFingerPrint));
-  assert(utils.isNumber(options.childIndex));
-  assert(Buffer.isBuffer(options.chainCode));
-  assert(Buffer.isBuffer(options.privateKey));
-  assert(options.depth <= 0xff, 'Depth is too high.');
-
-  if (options.network)
-    this.network = bcoin.network.get(options.network);
-
-  this.depth = options.depth;
-  this.parentFingerPrint = options.parentFingerPrint;
-  this.childIndex = options.childIndex;
-  this.chainCode = options.chainCode;
-  this.privateKey = options.privateKey;
-  this.publicKey = ec.publicKeyCreate(options.privateKey, true);
-
-  if (options.mnemonic) {
-    assert(options.mnemonic instanceof Mnemonic);
-    this.mnemonic = options.mnemonic;
-  }
-
-  if (options.xprivkey) {
-    assert(typeof options.xprivkey === 'string');
-    this._xprivkey = options.xprivkey;
-  }
-
-  return this;
-};
-
-/**
- * Instantiate HD private key from options object.
- * @param {Object} options
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromOptions = function fromOptions(options) {
-  return new HDPrivateKey().fromOptions(options);
-};
-
-HDPrivateKey.prototype.__defineGetter__('hdPublicKey', function() {
-  var key = this._hdPublicKey;
-
-  if (!key) {
-    key = new HDPublicKey();
-    key.network = this.network;
-    key.depth = this.depth;
-    key.parentFingerPrint = this.parentFingerPrint;
-    key.childIndex = this.childIndex;
-    key.chainCode = this.chainCode;
-    key.publicKey = this.publicKey;
-    this._hdPublicKey = key;
-  }
-
-  return key;
-});
-
-HDPrivateKey.prototype.__defineGetter__('xprivkey', function() {
-  if (!this._xprivkey)
-    this._xprivkey = this.toBase58();
-  return this._xprivkey;
-});
-
-HDPrivateKey.prototype.__defineGetter__('xpubkey', function() {
-  return this.hdPublicKey.xpubkey;
-});
-
-/**
- * Destroy the key (zeroes chain code, privkey, and pubkey).
- * @param {Boolean} pub - Destroy hd public key as well.
- */
-
-HDPrivateKey.prototype.destroy = function destroy(pub) {
-  this.depth = 0;
-  this.parentFingerPrint.fill(0);
-  this.childIndex = 0;
-  this.chainCode.fill(0);
-  this.privateKey.fill(0);
-  this.publicKey.fill(0);
-
-  if (this.fingerPrint) {
-    this.fingerPrint.fill(0);
-    this.fingerPrint = null;
-  }
-
-  if (this._hdPublicKey) {
-    if (pub)
-      this._hdPublicKey.destroy();
-    this._hdPublicKey = null;
-  }
-
-  this._xprivkey = null;
-
-  if (this.mnemonic) {
-    this.mnemonic.destroy();
-    this.mnemonic = null;
-  }
-};
-
-/**
- * Derive a child key.
- * @param {Number|String} - Child index or path.
- * @param {Boolean?} hardened - Whether the derivation should be hardened.
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.prototype.derive = function derive(index, hardened) {
-  var p, id, data, hash, left, right, key, child;
-
-  if (typeof index === 'string')
-    return this.derivePath(index);
-
-  hardened = index >= constants.hd.HARDENED ? true : hardened;
-
-  if (index < constants.hd.HARDENED && hardened)
-    index += constants.hd.HARDENED;
-
-  if (!(index >= 0 && index < constants.hd.MAX_INDEX))
-    throw new Error('Index out of range.');
-
-  if (this.depth >= 0xff)
-    throw new Error('Depth too high.');
-
-  id = this.getID(index);
-  child = HD.cache.get(id);
-
-  if (child)
-    return child;
-
-  p = new BufferWriter();
-
-  if (hardened) {
-    p.writeU8(0);
-    p.writeBytes(this.privateKey);
-    p.writeU32BE(index);
-  } else {
-    p.writeBytes(this.publicKey);
-    p.writeU32BE(index);
-  }
-
-  data = p.render();
-
-  hash = utils.hmac('sha512', data, this.chainCode);
-  left = hash.slice(0, 32);
-  right = hash.slice(32, 64);
-
-  try {
-    key = ec.privateKeyTweakAdd(this.privateKey, left);
-  } catch (e) {
-    return this.derive(index + 1);
-  }
-
-  if (!this.fingerPrint)
-    this.fingerPrint = utils.hash160(this.publicKey).slice(0, 4);
-
-  child = new HDPrivateKey();
-  child.network = this.network;
-  child.depth = this.depth + 1;
-  child.parentFingerPrint = this.fingerPrint;
-  child.childIndex = index;
-  child.chainCode = right;
-  child.privateKey = key;
-  child.publicKey = ec.publicKeyCreate(key, true);
-
-  HD.cache.set(id, child);
-
-  return child;
-};
-
-/**
- * Unique HD key ID.
- * @private
- * @param {Number} index
- * @returns {String}
- */
-
-HDPrivateKey.prototype.getID = function getID(index) {
-  return this.network.keyPrefix.xprivkey58
-    + this.publicKey.toString('hex')
-    + index;
-};
-
-/**
- * Derive a BIP44 account key.
- * @param {Number} accountIndex
- * @returns {HDPrivateKey}
- * @throws Error if key is not a master key.
- */
-
-HDPrivateKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex) {
-  assert(utils.isNumber(accountIndex), 'Account index must be a number.');
-  assert(this.isMaster(), 'Cannot derive account index.');
-  return this
-    .derive(44, true)
-    .derive(this.network.type === 'main' ? 0 : 1, true)
-    .derive(accountIndex, true);
-};
-
-/**
- * Derive a BIP45 purpose key.
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.prototype.derivePurpose45 = function derivePurpose45() {
-  assert(this.isMaster(), 'Cannot derive purpose 45.');
-  return this.derive(45, true);
-};
-
-/**
- * Test whether the key is a master key.
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.isMaster = function isMaster() {
-  return this.depth === 0
-    && this.childIndex === 0
-    && this.parentFingerPrint.readUInt32LE(0, true) === 0;
-};
-
-/**
- * Test whether the key is (most likely) a BIP44 account key.
- * @param {Number?} accountIndex
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.isAccount44 = function isAccount44(accountIndex) {
-  if (accountIndex != null) {
-    if (this.childIndex !== constants.hd.HARDENED + accountIndex)
-      return false;
-  }
-  return this.depth === 3 && this.childIndex >= constants.hd.HARDENED;
-};
-
-/**
- * Test whether the key is a BIP45 purpose key.
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.isPurpose45 = function isPurpose45() {
-  return this.depth === 1 && this.childIndex === constants.hd.HARDENED + 45;
-};
-
-/**
- * Test whether an object is in the form of a base58 xprivkey.
- * @param {String} data
- * @returns {Boolean}
- */
-
-HDPrivateKey.isExtended = function isExtended(data) {
-  var i, type, prefix;
-
-  if (typeof data !== 'string')
-    return false;
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xprivkey58;
-    if (data.indexOf(prefix) === 0)
-      return true;
-  }
-
-  return false;
-};
-
-/**
- * Test whether a buffer has a valid network prefix.
- * @param {Buffer} data
- * @returns {NetworkType}
- */
-
-HDPrivateKey.hasPrefix = function hasPrefix(data) {
-  var i, version, prefix, type;
-
-  if (!Buffer.isBuffer(data))
-    return false;
-
-  version = data.readUInt32BE(0, true);
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xprivkey;
-    if (version === prefix)
-      return type;
-  }
-
-  return false;
-};
-
-/**
- * Test whether a string is a valid path.
- * @param {String} path
- * @param {Boolean?} hardened
- * @returns {Boolean}
- */
-
-HDPrivateKey.isValidPath = function isValidPath(path) {
-  if (typeof path !== 'string')
-    return false;
-
-  try {
-    HD.parsePath(path, constants.hd.MAX_INDEX);
-    return true;
-  } catch (e) {
-    return false;
-  }
-};
-
-/**
- * Derive a key from a derivation path.
- * @param {String} path
- * @returns {HDPrivateKey}
- * @throws Error if `path` is not a valid path.
- */
-
-HDPrivateKey.prototype.derivePath = function derivePath(path) {
-  var indexes = HD.parsePath(path, constants.hd.MAX_INDEX);
-  var key = this;
-  var i;
-
-  for (i = 0; i < indexes.length; i++)
-    key = key.derive(indexes[i]);
-
-  return key;
-};
-
-/**
- * Compare a key against an object.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.equal = function equal(obj) {
-  if (!HDPrivateKey.isHDPrivateKey(obj))
-    return false;
-
-  return this.network === obj.network
-    && this.depth === obj.depth
-    && utils.equal(this.parentFingerPrint, obj.parentFingerPrint)
-    && this.childIndex === obj.childIndex
-    && utils.equal(this.chainCode, obj.chainCode)
-    && utils.equal(this.privateKey, obj.privateKey);
-};
-
-/**
- * Compare a key against an object.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.compare = function compare(key) {
-  var cmp;
-
-  if (!HDPrivateKey.isHDPrivateKey(key))
-    return 1;
-
-  cmp = this.depth - key.depth;
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.parentFingerPrint, key.parentFingerPrint);
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = this.childIndex - key.childIndex;
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.chainCode, key.chainCode);
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.privateKey, key.privateKey);
-
-  if (cmp !== 0)
-    return cmp;
-
-  return 0;
-};
-
-/**
- * Inject properties from seed.
- * @private
- * @param {Buffer} seed
- * @param {(Network|NetworkType)?} network
- */
-
-HDPrivateKey.prototype.fromSeed = function fromSeed(seed, network) {
-  var hash, left, right;
-
-  assert(Buffer.isBuffer(seed));
-
-  if (!(seed.length * 8 >= constants.hd.MIN_ENTROPY
-      && seed.length * 8 <= constants.hd.MAX_ENTROPY)) {
-    throw new Error('Entropy not in range.');
-  }
-
-  hash = utils.hmac('sha512', seed, 'Bitcoin seed');
-
-  left = hash.slice(0, 32);
-  right = hash.slice(32, 64);
-
-  // Only a 1 in 2^127 chance of happening.
-  if (!ec.privateKeyVerify(left))
-    throw new Error('Master private key is invalid.');
-
-  this.network = bcoin.network.get(network);
-  this.depth = 0;
-  this.parentFingerPrint = new Buffer([0, 0, 0, 0]);
-  this.childIndex = 0;
-  this.chainCode = right;
-  this.privateKey = left;
-  this.publicKey = ec.publicKeyCreate(left, true);
-
-  return this;
-};
-
-/**
- * Instantiate an hd private key from a 512 bit seed.
- * @param {Buffer} seed
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromSeed = function fromSeed(seed, network) {
-  return new HDPrivateKey().fromSeed(seed, network);
-};
-
-/**
- * Inject properties from a mnemonic.
- * @private
- * @param {Mnemonic|Object} mnemonic
- * @param {(Network|NetworkType)?} network
- */
-
-HDPrivateKey.prototype.fromMnemonic = function fromMnemonic(mnemonic, network) {
-  if (!(mnemonic instanceof Mnemonic))
-    mnemonic = new Mnemonic(mnemonic);
-  this.fromSeed(mnemonic.toSeed(), network);
-  this.mnemonic = mnemonic;
-  return this;
-};
-
-/**
- * Instantiate an hd private key from a mnemonic.
- * @param {Mnemonic|Object} mnemonic
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromMnemonic = function fromMnemonic(mnemonic, network) {
-  return new HDPrivateKey().fromMnemonic(mnemonic, network);
-};
-
-/**
- * Inject properties from privateKey and entropy.
- * @private
- * @param {Buffer} key
- * @param {Buffer} entropy
- * @param {(Network|NetworkType)?} network
- */
-
-HDPrivateKey.prototype.fromKey = function fromKey(key, entropy, network) {
-  assert(Buffer.isBuffer(key) && key.length === 32);
-  assert(Buffer.isBuffer(entropy) && entropy.length === 32);
-  this.network = bcoin.network.get(network);
-  this.depth = 0;
-  this.parentFingerPrint = new Buffer([0, 0, 0, 0]);
-  this.childIndex = 0;
-  this.chainCode = entropy;
-  this.privateKey = key;
-  this.publicKey = ec.publicKeyCreate(key, true);
-  return this;
-};
-
-/**
- * Create an hd private key from a key and entropy bytes.
- * @param {Buffer} key
- * @param {Buffer} entropy
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromKey = function fromKey(key, entropy, network) {
-  return new HDPrivateKey().fromKey(key, entropy, network);
-};
-
-/**
- * Generate an hd private key.
- * @param {(Network|NetworkType)?} network
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.generate = function generate(network) {
-  var key = ec.generatePrivateKey();
-  var entropy = ec.random(32);
-  return HDPrivateKey.fromKey(key, entropy, network);
-};
-
-/**
- * Inject properties from base58 key.
- * @private
- * @param {Base58String} xkey
- */
-
-HDPrivateKey.prototype.fromBase58 = function fromBase58(xkey) {
-  this.fromRaw(utils.fromBase58(xkey));
-  this._xprivkey = xkey;
-  return this;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} raw
- */
-
-HDPrivateKey.prototype.fromRaw = function fromRaw(raw) {
-  var p = new BufferReader(raw);
-  var i, version, type, prefix;
-
-  version = p.readU32BE();
-  this.depth = p.readU8();
-  this.parentFingerPrint = p.readBytes(4);
-  this.childIndex = p.readU32BE();
-  this.chainCode = p.readBytes(32);
-  p.readU8();
-  this.privateKey = p.readBytes(32);
-  p.verifyChecksum();
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xprivkey;
-    if (version === prefix)
-      break;
-  }
-
-  assert(i < networks.types.length, 'Network not found.');
-
-  this.publicKey = ec.publicKeyCreate(this.privateKey, true);
-  this.network = bcoin.network.get(type);
-
-  return this;
-};
-
-/**
- * Serialize key to a base58 string.
- * @param {(Network|NetworkType)?} network
- * @returns {Base58String}
- */
-
-HDPrivateKey.prototype.toBase58 = function toBase58(network) {
-  return utils.toBase58(this.toRaw(network));
-};
-
-/**
- * Serialize the key.
- * @param {(Network|NetworkType)?} network
- * @returns {Buffer}
- */
-
-HDPrivateKey.prototype.toRaw = function toRaw(network, writer) {
-  var p = new BufferWriter(writer);
-
-  if (!network)
-    network = this.network;
-
-  network = bcoin.network.get(network);
-
-  p.writeU32BE(network.keyPrefix.xprivkey);
-  p.writeU8(this.depth);
-  p.writeBytes(this.parentFingerPrint);
-  p.writeU32BE(this.childIndex);
-  p.writeBytes(this.chainCode);
-  p.writeU8(0);
-  p.writeBytes(this.privateKey);
-  p.writeChecksum();
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Serialize the key in "extended"
- * format (includes the mnemonic).
- * @param {(Network|NetworkType)?} network
- * @returns {Buffer}
- */
-
-HDPrivateKey.prototype.toExtended = function toExtended(network, writer) {
-  var p = new BufferWriter(writer);
-
-  this.toRaw(network, p);
-
-  if (this.mnemonic) {
-    p.writeU8(1);
-    this.mnemonic.toRaw(p);
-  } else {
-    p.writeU8(0);
-  }
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from extended serialized data.
- * @private
- * @param {Buffer} data
- */
-
-HDPrivateKey.prototype.fromExtended = function fromExtended(data) {
-  var p = new BufferReader(data);
-  this.fromRaw(p);
-  if (p.readU8() === 1)
-    this.mnemonic = Mnemonic.fromRaw(p);
-  return this;
-};
-
-/**
- * Instantiate key from "extended" serialized data.
- * @param {Buffer} data
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromExtended = function fromExtended(data) {
-  return new HDPrivateKey().fromExtended(data);
-};
-
-/**
- * Instantiate an HD private key from a base58 string.
- * @param {Base58String} xkey
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromBase58 = function fromBase58(xkey) {
-  return new HDPrivateKey().fromBase58(xkey);
-};
-
-/**
- * Instantiate key from serialized data.
- * @param {Buffer} raw
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromRaw = function fromRaw(raw) {
-  return new HDPrivateKey().fromRaw(raw);
-};
-
-/**
- * Convert key to a more json-friendly object.
- * @returns {Object}
- */
-
-HDPrivateKey.prototype.toJSON = function toJSON() {
-  return {
-    xprivkey: this.xprivkey,
-    mnemonic: this.mnemonic ? this.mnemonic.toJSON() : null
-  };
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {Object} json
- */
-
-HDPrivateKey.prototype.fromJSON = function fromJSON(json) {
-  assert(json.xprivkey, 'Could not handle key JSON.');
-
-  this.fromBase58(json.xprivkey);
-
-  if (json.mnemonic)
-    this.mnemonic = Mnemonic.fromJSON(json.mnemonic);
-
-  return this;
-};
-
-/**
- * Instantiate an HDPrivateKey from a jsonified key object.
- * @param {Object} json - The jsonified key object.
- * @returns {HDPrivateKey}
- */
-
-HDPrivateKey.fromJSON = function fromJSON(json) {
-  return new HDPrivateKey().fromJSON(json);
-};
-
-/**
- * Test whether an object is an HDPrivateKey.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPrivateKey.isHDPrivateKey = function isHDPrivateKey(obj) {
-  return obj
-    && typeof obj.derive === 'function'
-    && typeof obj.toExtended === 'function'
-    && obj.chainCode !== undefined;
-};
-
-/**
- * HDPublicKey
- * @exports HDPublicKey
- * @constructor
- * @param {Object|Base58String} options
- * @param {Base58String?} options.xkey - Serialized base58 key.
- * @param {Number?} options.depth
- * @param {Buffer?} options.parentFingerPrint
- * @param {Number?} options.childIndex
- * @param {Buffer?} options.chainCode
- * @param {Buffer?} options.publicKey
- * @property {Network} network
- * @property {Base58String} xpubkey
- * @property {Number} depth
- * @property {Buffer} parentFingerPrint
- * @property {Number} childIndex
- * @property {Buffer} chainCode
- * @property {Buffer} publicKey
- */
-
-function HDPublicKey(options) {
-  if (!(this instanceof HDPublicKey))
-    return new HDPublicKey(options);
-
-  this.network = bcoin.network.get();
-  this.depth = 0;
-  this.parentFingerPrint = FINGER_PRINT;
-  this.childIndex = 0;
-  this.chainCode = constants.ZERO_HASH;
-  this.publicKey = constants.ZERO_KEY;
-
-  this.fingerPrint = null;
-
-  this._xpubkey = null;
-
-  this.hdPublicKey = this;
-  this.hdPrivateKey = null;
-
-  if (options)
-    this.fromOptions(options);
-}
-
-utils.inherits(HDPublicKey, HD);
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-HDPublicKey.prototype.fromOptions = function fromOptions(options) {
-  assert(options, 'No options for HDPublicKey');
-  assert(utils.isNumber(options.depth));
-  assert(Buffer.isBuffer(options.parentFingerPrint));
-  assert(utils.isNumber(options.childIndex));
-  assert(Buffer.isBuffer(options.chainCode));
-  assert(Buffer.isBuffer(options.publicKey));
-
-  if (options.network)
-    this.network = bcoin.network.get(options.network);
-
-  this.depth = options.depth;
-  this.parentFingerPrint = options.parentFingerPrint;
-  this.childIndex = options.childIndex;
-  this.chainCode = options.chainCode;
-  this.publicKey = options.publicKey;
-
-  if (options.xpubkey) {
-    assert(typeof options.xpubkey === 'string');
-    this._xpubkey = options.xpubkey;
-  }
-
-  return this;
-};
-
-/**
- * Instantiate HD public key from options object.
- * @param {Object} options
- * @returns {HDPublicKey}
- */
-
-HDPublicKey.fromOptions = function fromOptions(options) {
-  return new HDPublicKey().fromOptions(options);
-};
-
-HDPublicKey.prototype.__defineGetter__('xpubkey', function() {
-  if (!this._xpubkey)
-    this._xpubkey = this.toBase58();
-  return this._xpubkey;
-});
-
-/**
- * Destroy the key (zeroes chain code and pubkey).
- */
-
-HDPublicKey.prototype.destroy = function destroy() {
-  this.depth = 0;
-  this.parentFingerPrint.fill(0);
-  this.childIndex = 0;
-  this.chainCode.fill(0);
-  this.publicKey.fill(0);
-
-  if (this.fingerPrint) {
-    this.fingerPrint.fill(0);
-    this.fingerPrint = null;
-  }
-
-  this._xpubkey = null;
-};
-
-/**
- * Derive a child key.
- * @param {Number|String} - Child index or path.
- * @param {Boolean?} hardened - Whether the derivation
- * should be hardened (throws if true).
- * @returns {HDPrivateKey}
- * @throws on `hardened`
- */
-
-HDPublicKey.prototype.derive = function derive(index, hardened) {
-  var p, id, data, hash, left, right, key, child;
-
-  if (typeof index === 'string')
-    return this.derivePath(index);
-
-  if (index >= constants.hd.HARDENED || hardened)
-    throw new Error('Index out of range.');
-
-  if (index < 0)
-    throw new Error('Index out of range.');
-
-  if (this.depth >= 0xff)
-    throw new Error('Depth too high.');
-
-  id = this.getID(index);
-  child = HD.cache.get(id);
-
-  if (child)
-    return child;
-
-  p = new BufferWriter();
-  p.writeBytes(this.publicKey);
-  p.writeU32BE(index);
-  data = p.render();
-
-  hash = utils.hmac('sha512', data, this.chainCode);
-  left = hash.slice(0, 32);
-  right = hash.slice(32, 64);
-
-  try {
-    key = ec.publicKeyTweakAdd(this.publicKey, left, true);
-  } catch (e) {
-    return this.derive(index + 1);
-  }
-
-  if (!this.fingerPrint)
-    this.fingerPrint = utils.hash160(this.publicKey).slice(0, 4);
-
-  child = new HDPublicKey();
-  child.network = this.network;
-  child.depth = this.depth + 1;
-  child.parentFingerPrint = this.fingerPrint;
-  child.childIndex = index;
-  child.chainCode = right;
-  child.publicKey = key;
-
-  HD.cache.set(id, child);
-
-  return child;
-};
-
-/**
- * Unique HD key ID.
- * @private
- * @param {Number} index
- * @returns {String}
- */
-
-HDPublicKey.prototype.getID = function getID(index) {
-  return this.network.keyPrefix.xpubkey58
-    + this.publicKey.toString('hex')
-    + index;
-};
-
-/**
- * Derive a BIP44 account key (does not derive, only ensures account key).
- * @method
- * @param {Number} accountIndex
- * @returns {HDPublicKey}
- * @throws Error if key is not already an account key.
- */
-
-HDPublicKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex) {
-  assert(this.isAccount44(accountIndex), 'Cannot derive account index.');
-  return this;
-};
-
-/**
- * Derive a BIP45 purpose key (does not derive, only ensures account key).
- * @method
- * @returns {HDPublicKey}
- * @throws Error if key is not already a purpose key.
- */
-
-HDPublicKey.prototype.derivePurpose45 = function derivePurpose45() {
-  assert(this.isPurpose45(), 'Cannot derive purpose 45.');
-  return this;
-};
-
-/**
- * Test whether the key is a master key.
- * @method
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.isMaster = HDPrivateKey.prototype.isMaster;
-
-/**
- * Test whether the key is (most likely) a BIP44 account key.
- * @method
- * @param {Number?} accountIndex
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.isAccount44 = HDPrivateKey.prototype.isAccount44;
-
-/**
- * Test whether the key is a BIP45 purpose key.
- * @method
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.isPurpose45 = HDPrivateKey.prototype.isPurpose45;
-
-/**
- * Test whether a string is a valid path.
- * @param {String} path
- * @param {Boolean?} hardened
- * @returns {Boolean}
- */
-
-HDPublicKey.isValidPath = function isValidPath(path) {
-  if (typeof path !== 'string')
-    return false;
-
-  try {
-    HD.parsePath(path, constants.hd.HARDENED);
-    return true;
-  } catch (e) {
-    return false;
-  }
-};
-
-/**
- * Derive a key from a derivation path.
- * @param {String} path
- * @returns {HDPublicKey}
- * @throws Error if `path` is not a valid path.
- * @throws Error if hardened.
- */
-
-HDPublicKey.prototype.derivePath = function derivePath(path) {
-  var indexes = HD.parsePath(path, constants.hd.HARDENED);
-  var key = this;
-  var i;
-
-  for (i = 0; i < indexes.length; i++)
-    key = key.derive(indexes[i]);
-
-  return key;
-};
-
-/**
- * Compare a key against an object.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.equal = function equal(obj) {
-  if (!HDPublicKey.isHDPublicKey(obj))
-    return false;
-
-  return this.network === obj.network
-    && this.depth === obj.depth
-    && utils.equal(this.parentFingerPrint, obj.parentFingerPrint)
-    && this.childIndex === obj.childIndex
-    && utils.equal(this.chainCode, obj.chainCode)
-    && utils.equal(this.publicKey, obj.publicKey);
-};
-
-/**
- * Compare a key against an object.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.compare = function compare(key) {
-  var cmp;
-
-  if (!HDPublicKey.isHDPublicKey(key))
-    return 1;
-
-  cmp = this.depth - key.depth;
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.parentFingerPrint, key.parentFingerPrint);
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = this.childIndex - key.childIndex;
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.chainCode, key.chainCode);
-
-  if (cmp !== 0)
-    return cmp;
-
-  cmp = utils.cmp(this.publicKey, key.publicKey);
-
-  if (cmp !== 0)
-    return cmp;
-
-  return 0;
-};
-
-/**
- * Convert key to a more json-friendly object.
- * @returns {Object}
- */
-
-HDPublicKey.prototype.toJSON = function toJSON() {
-  return {
-    xpubkey: this.xpubkey
-  };
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {Object} json
- */
-
-HDPublicKey.prototype.fromJSON = function fromJSON(json) {
-  assert(json.xpubkey, 'Could not handle HD key JSON.');
-  this.fromBase58(json.xpubkey);
-  return this;
-};
-
-/**
- * Instantiate an HDPrivateKey from a jsonified key object.
- * @param {Object} json - The jsonified transaction object.
- * @returns {HDPrivateKey}
- */
-
-HDPublicKey.fromJSON = function fromJSON(json) {
-  return new HDPublicKey().fromJSON(json);
-};
-
-/**
- * Test whether an object is in the form of a base58 xpubkey.
- * @param {String} data
- * @returns {Boolean}
- */
-
-HDPublicKey.isExtended = function isExtended(data) {
-  var i, type, prefix;
-
-  if (typeof data !== 'string')
-    return false;
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xpubkey58;
-    if (data.indexOf(prefix) === 0)
-      return true;
-  }
-
-  return false;
-};
-
-/**
- * Test whether a buffer has a valid network prefix.
- * @param {Buffer} data
- * @returns {NetworkType}
- */
-
-HDPublicKey.hasPrefix = function hasPrefix(data) {
-  var i, version, prefix, type;
-
-  if (!Buffer.isBuffer(data))
-    return false;
-
-  version = data.readUInt32BE(0, true);
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xpubkey;
-    if (version === prefix)
-      return type;
-  }
-
-  return false;
-};
-
-/**
- * Inject properties from a base58 key.
- * @private
- * @param {Base58String} xkey
- */
-
-HDPublicKey.prototype.fromBase58 = function fromBase58(xkey) {
-  this.fromRaw(utils.fromBase58(xkey));
-  this._xpubkey = xkey;
-  return this;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} raw
- */
-
-HDPublicKey.prototype.fromRaw = function fromRaw(raw) {
-  var p = new BufferReader(raw);
-  var i, version, type, prefix;
-
-  version = p.readU32BE();
-  this.depth = p.readU8();
-  this.parentFingerPrint = p.readBytes(4);
-  this.childIndex = p.readU32BE();
-  this.chainCode = p.readBytes(32);
-  this.publicKey = p.readBytes(33);
-  p.verifyChecksum();
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.xpubkey;
-    if (version === prefix)
-      break;
-  }
-
-  assert(i < networks.types.length, 'Network not found.');
-
-  this.network = bcoin.network.get(type);
-
-  return this;
-};
-
-/**
- * Serialize key data to base58 extended key.
- * @param {Network|String} network
- * @returns {Base58String}
- */
-
-HDPublicKey.prototype.toBase58 = function toBase58(network) {
-  return utils.toBase58(this.toRaw(network));
-};
-
-/**
- * Serialize the key.
- * @param {Network|NetworkType} network
- * @returns {Buffer}
- */
-
-HDPublicKey.prototype.toRaw = function toRaw(network, writer) {
-  var p = new BufferWriter(writer);
-
-  if (!network)
-    network = this.network;
-
-  network = bcoin.network.get(network);
-
-  p.writeU32BE(network.keyPrefix.xpubkey);
-  p.writeU8(this.depth);
-  p.writeBytes(this.parentFingerPrint);
-  p.writeU32BE(this.childIndex);
-  p.writeBytes(this.chainCode);
-  p.writeBytes(this.publicKey);
-  p.writeChecksum();
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Instantiate an HD public key from a base58 string.
- * @param {Base58String} xkey
- * @returns {HDPublicKey}
- */
-
-HDPublicKey.fromBase58 = function fromBase58(xkey) {
-  return new HDPublicKey().fromBase58(xkey);
-};
-
-/**
- * Instantiate key from serialized data.
- * @param {Buffer} raw
- * @returns {HDPublicKey}
- */
-
-HDPublicKey.fromRaw = function fromRaw(data) {
-  return new HDPublicKey().fromRaw(data);
-};
-
-/**
- * Test whether an object is a HDPublicKey.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-HDPublicKey.isHDPublicKey = function isHDPublicKey(obj) {
-  return obj
-    && typeof obj.derive === 'function'
-    && typeof obj.toExtended !== 'function'
-    && obj.chainCode !== undefined;
-};
-
-[HDPrivateKey, HDPublicKey].forEach(function(HD) {
-  /**
-   * Get private key.
-   * @memberof HDPrivateKey#
-   * @memberof HDPublicKey#
-   * @method
-   * @returns {Buffer}
-   */
-
-  HD.prototype.getPrivateKey = KeyRing.prototype.getPrivateKey;
-
-  /**
-   * Get public key.
-   * @memberof HDPrivateKey#
-   * @memberof HDPublicKey#
-   * @method
-   * @returns {Buffer}
-   */
-
-  HD.prototype.getPublicKey = KeyRing.prototype.getPublicKey;
-
-  /**
-   * Sign message.
-   * @memberof HDPrivateKey#
-   * @memberof HDPublicKey#
-   * @param {Buffer} msg
-   * @returns {Buffer}
-   */
-
-  HD.prototype.sign = KeyRing.prototype.sign;
-
-  /**
-   * Verify message.
-   * @memberof HDPrivateKey#
-   * @memberof HDPublicKey#
-   * @param {Buffer} msg
-   * @param {Buffer} sig
-   * @returns {Boolean}
-   */
-
-  HD.prototype.verify = KeyRing.prototype.verify;
-
-  /**
-   * Convert HDPrivateKey to a KeyRing.
-   * @returns {KeyRing}
-   */
-
-  HD.prototype.toKeyRing = function toKeyRing() {
-    return new KeyRing(this.privateKey || this.publicKey, this.network);
-  };
-
-  /**
-   * Whether the key prefers a
-   * compressed public key.
-   * Always true.
-   * @memberof HDPrivateKey#
-   * @memberof HDPublicKey#
-   * @type {Boolean}
-   */
-
-  HD.prototype.compressed = true;
-});
-
-/**
- * Convert HDPrivateKey to CBitcoinSecret.
- * @returns {Base58String}
- */
-
-HDPrivateKey.prototype.toSecret = function toSecret(network) {
-  return this.toKeyRing().toSecret(network);
-};
-
-/*
- * Helpers
- */
-
-function nfkd(str) {
-  if (str.normalize)
-    return str.normalize('NFKD');
-
-  if (!unorm)
-    unorm = require('../../../vendor/unorm');
-
-  return unorm.nfkd(str);
-}
-
-/*
- * Expose
- */
-
-exports = HD;
-exports.Mnemonic = Mnemonic;
-exports.PrivateKey = HDPrivateKey;
-exports.PublicKey = HDPublicKey;
-
-module.exports = HD;
diff --git a/lib/bcoin/primitives/input.js b/lib/bcoin/primitives/input.js
index ca872d89..a7ca2f52 100644
--- a/lib/bcoin/primitives/input.js
+++ b/lib/bcoin/primitives/input.js
@@ -11,171 +11,7 @@ var bcoin = require('../env');
 var utils = require('../utils/utils');
 var assert = utils.assert;
 var constants = bcoin.constants;
-
-/**
- * Represents a COutPoint.
- * @exports Outpoint
- * @constructor
- * @param {Hash?} hash
- * @param {Number?} index
- * @property {Hash} hash
- * @property {Number} index
- */
-
-function Outpoint(hash, index) {
-  if (!(this instanceof Outpoint))
-    return new Outpoint(hash, index);
-
-  this.hash = hash || constants.NULL_HASH;
-  this.index = index != null ? index : 0xffffffff;
-}
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-Outpoint.prototype.fromOptions = function fromOptions(options) {
-  assert(typeof options.hash === 'string');
-  assert(utils.isNumber(options.index));
-  this.hash = options.hash;
-  this.index = options.index;
-  return this;
-};
-
-/**
- * Instantate outpoint from options object.
- * @param {Object} options
- * @returns {Outpoint}
- */
-
-Outpoint.fromOptions = function fromOptions(options) {
-  return new Outpoint().fromOptions(options);
-};
-
-/**
- * Test whether the outpoint is null (hash of zeroes
- * with max-u32 index). Used to detect coinbases.
- * @returns {Boolean}
- */
-
-Outpoint.prototype.isNull = function isNull() {
-  return this.index === 0xffffffff && this.hash === constants.NULL_HASH;
-};
-
-/**
- * Serialize outpoint.
- * @returns {Buffer}
- */
-
-Outpoint.prototype.toRaw = function toRaw(writer) {
-  var p = bcoin.writer(writer);
-
-  p.writeHash(this.hash);
-  p.writeU32(this.index);
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- */
-
-Outpoint.prototype.fromRaw = function fromRaw(data) {
-  var p = bcoin.reader(data);
-  this.hash = p.readHash('hex');
-  this.index = p.readU32();
-  return this;
-};
-
-/**
- * Instantiate outpoint from serialized data.
- * @param {Buffer} data
- * @returns {Outpoint}
- */
-
-Outpoint.fromRaw = function fromRaw(data) {
-  return new Outpoint().fromRaw(data);
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @params {Object} json
- */
-
-Outpoint.prototype.fromJSON = function fromJSON(json) {
-  assert(typeof json.hash === 'string');
-  assert(utils.isNumber(json.index));
-  this.hash = utils.revHex(json.hash);
-  this.index = json.index;
-  return this;
-};
-
-/**
- * Convert the outpoint to an object suitable
- * for JSON serialization. Note that the hash
- * will be reversed to abide by bitcoind's legacy
- * of little-endian uint256s.
- * @returns {Object}
- */
-
-Outpoint.prototype.toJSON = function toJSON() {
-  return {
-    hash: utils.revHex(this.hash),
-    index: this.index
-  };
-};
-
-/**
- * Instantiate outpoint from json object.
- * @param {Object} json
- * @returns {Outpoint}
- */
-
-Outpoint.fromJSON = function fromJSON(json) {
-  return new Outpoint().fromJSON(json);
-};
-
-/**
- * Inject properties from tx.
- * @private
- * @param {TX} tx
- * @param {Number} index
- */
-
-Outpoint.prototype.fromTX = function fromTX(tx, index) {
-  assert(utils.isNumber(index));
-  this.hash = tx.hash('hex');
-  this.index = index;
-  return this;
-};
-
-/**
- * Instantiate outpoint from tx.
- * @param {TX} tx
- * @param {Number} index
- * @returns {Outpoint}
- */
-
-Outpoint.fromTX = function fromTX(tx, index) {
-  return new Outpoint().fromTX(tx, index);
-};
-
-/**
- * Convert the outpoint to a user-friendly string.
- * @returns {String}
- */
-
-Outpoint.prototype.inspect = function inspect() {
-  return '<Outpoint: ' + utils.revHex(this.hash) + '/' + this.index + '>';
-};
+var Outpoint = require('./outpoint');
 
 /**
  * Represents a transaction input.
@@ -617,6 +453,4 @@ Input.isInput = function isInput(obj) {
  * Expose
  */
 
-exports = Input;
-exports.Outpoint = Outpoint;
-module.exports = exports;
+module.exports = Input;
diff --git a/lib/bcoin/primitives/invitem.js b/lib/bcoin/primitives/invitem.js
new file mode 100644
index 00000000..4f8da655
--- /dev/null
+++ b/lib/bcoin/primitives/invitem.js
@@ -0,0 +1,117 @@
+/*!
+ * invitem.js - inv item object for bcoin
+ * Copyright (c) 2014-2015, Fedor Indutny (MIT License)
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var constants = require('../protocol/constants');
+
+/**
+ * Inv Item
+ * @param {Number} type
+ * @param {Hash} hash
+ * @property {InvType} type
+ * @property {Hash} hash
+ */
+
+function InvItem(type, hash) {
+  if (!(this instanceof InvItem))
+    return new InvItem(type, hash);
+
+  this.type = type;
+  this.hash = hash;
+}
+
+/**
+ * Serialize inv item.
+ * @returns {Buffer}
+ */
+
+InvItem.prototype.toRaw = function toRaw(writer) {
+  var p = bcoin.writer(writer);
+
+  p.writeU32(this.type);
+  p.writeHash(this.hash);
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @param {Buffer} data
+ */
+
+InvItem.prototype.fromRaw = function fromRaw(data) {
+  var p = bcoin.reader(data);
+  this.type = p.readU32();
+  this.hash = p.readHash('hex');
+  return this;
+};
+
+/**
+ * Instantiate inv item from serialized data.
+ * @param {Buffer} data
+ * @param {String?} enc
+ * @returns {InvItem}
+ */
+
+InvItem.fromRaw = function fromRaw(data, enc) {
+  if (typeof data === 'string')
+    data = new Buffer(data, enc);
+  return new InvItem().fromRaw(data);
+};
+
+/**
+ * Test whether the inv item is a block.
+ * @returns {Boolean}
+ */
+
+InvItem.prototype.isBlock = function isBlock() {
+  switch (this.type) {
+    case constants.inv.BLOCK:
+    case constants.inv.WITNESS_BLOCK:
+    case constants.inv.FILTERED_BLOCK:
+    case constants.inv.WITNESS_FILTERED_BLOCK:
+    case constants.inv.CMPCT_BLOCK:
+      return true;
+    default:
+      return false;
+  }
+};
+
+/**
+ * Test whether the inv item is a tx.
+ * @returns {Boolean}
+ */
+
+InvItem.prototype.isTX = function isTX() {
+  switch (this.type) {
+    case constants.inv.TX:
+    case constants.inv.WITNESS_TX:
+      return true;
+    default:
+      return false;
+  }
+};
+
+/**
+ * Test whether the inv item has the witness bit set.
+ * @returns {Boolean}
+ */
+
+InvItem.prototype.hasWitness = function hasWitness() {
+  return (this.type & constants.WITNESS_MASK) !== 0;
+};
+
+/*
+ * Expose
+ */
+
+module.exports = InvItem;
diff --git a/lib/bcoin/primitives/keyring.js b/lib/bcoin/primitives/keyring.js
index 6cbbfb62..b56cdc1e 100644
--- a/lib/bcoin/primitives/keyring.js
+++ b/lib/bcoin/primitives/keyring.js
@@ -882,11 +882,11 @@ function toKey(opt) {
   if (!opt)
     return opt;
 
-  if (opt.getPrivateKey)
-    return opt.getPrivateKey();
+  if (opt.privateKey)
+    return opt.privateKey
 
-  if (opt.getPublicKey)
-    return opt.getPublicKey();
+  if (opt.publicKey)
+    return opt.publicKey;
 
   return opt;
 }
diff --git a/lib/bcoin/primitives/outpoint.js b/lib/bcoin/primitives/outpoint.js
new file mode 100644
index 00000000..34f1f50a
--- /dev/null
+++ b/lib/bcoin/primitives/outpoint.js
@@ -0,0 +1,183 @@
+/*!
+ * outpoint.js - outpoint object for bcoin
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var constants = bcoin.constants;
+
+/**
+ * Represents a COutPoint.
+ * @exports Outpoint
+ * @constructor
+ * @param {Hash?} hash
+ * @param {Number?} index
+ * @property {Hash} hash
+ * @property {Number} index
+ */
+
+function Outpoint(hash, index) {
+  if (!(this instanceof Outpoint))
+    return new Outpoint(hash, index);
+
+  this.hash = hash || constants.NULL_HASH;
+  this.index = index != null ? index : 0xffffffff;
+}
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+Outpoint.prototype.fromOptions = function fromOptions(options) {
+  assert(typeof options.hash === 'string');
+  assert(utils.isNumber(options.index));
+  this.hash = options.hash;
+  this.index = options.index;
+  return this;
+};
+
+/**
+ * Instantate outpoint from options object.
+ * @param {Object} options
+ * @returns {Outpoint}
+ */
+
+Outpoint.fromOptions = function fromOptions(options) {
+  return new Outpoint().fromOptions(options);
+};
+
+/**
+ * Test whether the outpoint is null (hash of zeroes
+ * with max-u32 index). Used to detect coinbases.
+ * @returns {Boolean}
+ */
+
+Outpoint.prototype.isNull = function isNull() {
+  return this.index === 0xffffffff && this.hash === constants.NULL_HASH;
+};
+
+/**
+ * Serialize outpoint.
+ * @returns {Buffer}
+ */
+
+Outpoint.prototype.toRaw = function toRaw(writer) {
+  var p = bcoin.writer(writer);
+
+  p.writeHash(this.hash);
+  p.writeU32(this.index);
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} data
+ */
+
+Outpoint.prototype.fromRaw = function fromRaw(data) {
+  var p = bcoin.reader(data);
+  this.hash = p.readHash('hex');
+  this.index = p.readU32();
+  return this;
+};
+
+/**
+ * Instantiate outpoint from serialized data.
+ * @param {Buffer} data
+ * @returns {Outpoint}
+ */
+
+Outpoint.fromRaw = function fromRaw(data) {
+  return new Outpoint().fromRaw(data);
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @params {Object} json
+ */
+
+Outpoint.prototype.fromJSON = function fromJSON(json) {
+  assert(typeof json.hash === 'string');
+  assert(utils.isNumber(json.index));
+  this.hash = utils.revHex(json.hash);
+  this.index = json.index;
+  return this;
+};
+
+/**
+ * Convert the outpoint to an object suitable
+ * for JSON serialization. Note that the hash
+ * will be reversed to abide by bitcoind's legacy
+ * of little-endian uint256s.
+ * @returns {Object}
+ */
+
+Outpoint.prototype.toJSON = function toJSON() {
+  return {
+    hash: utils.revHex(this.hash),
+    index: this.index
+  };
+};
+
+/**
+ * Instantiate outpoint from json object.
+ * @param {Object} json
+ * @returns {Outpoint}
+ */
+
+Outpoint.fromJSON = function fromJSON(json) {
+  return new Outpoint().fromJSON(json);
+};
+
+/**
+ * Inject properties from tx.
+ * @private
+ * @param {TX} tx
+ * @param {Number} index
+ */
+
+Outpoint.prototype.fromTX = function fromTX(tx, index) {
+  assert(utils.isNumber(index));
+  this.hash = tx.hash('hex');
+  this.index = index;
+  return this;
+};
+
+/**
+ * Instantiate outpoint from tx.
+ * @param {TX} tx
+ * @param {Number} index
+ * @returns {Outpoint}
+ */
+
+Outpoint.fromTX = function fromTX(tx, index) {
+  return new Outpoint().fromTX(tx, index);
+};
+
+/**
+ * Convert the outpoint to a user-friendly string.
+ * @returns {String}
+ */
+
+Outpoint.prototype.inspect = function inspect() {
+  return '<Outpoint: ' + utils.revHex(this.hash) + '/' + this.index + '>';
+};
+
+/*
+ * Expose
+ */
+
+module.exports = Outpoint;
diff --git a/lib/bcoin/script/opcode.js b/lib/bcoin/script/opcode.js
new file mode 100644
index 00000000..b060f2f3
--- /dev/null
+++ b/lib/bcoin/script/opcode.js
@@ -0,0 +1,176 @@
+/*!
+ * script.js - script interpreter for bcoin
+ * Copyright (c) 2014-2015, Fedor Indutny (MIT License)
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var bn = require('bn.js');
+var constants = bcoin.constants;
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var opcodes = constants.opcodes;
+
+/**
+ * A simple struct which contains
+ * an opcode and pushdata buffer.
+ * @exports Opcode
+ * @constructor
+ * @param {Number} value - Opcode.
+ * @param {Buffer?} data - Pushdata buffer.
+ * @property {Number} value
+ * @property {Buffer|null} data
+ */
+
+function Opcode(value, data) {
+  if (!(this instanceof Opcode))
+    return new Opcode(value, data);
+
+  this.value = value;
+  this.data = data || null;
+}
+
+/**
+ * Encode the opcode.
+ * @returns {Buffer}
+ */
+
+Opcode.prototype.toRaw = function toRaw(writer) {
+  return bcoin.script.encode([this], writer);
+};
+
+/**
+ * Instantiate an opcode from a number opcode.
+ * @param {Number} op
+ * @returns {Opcode}
+ */
+
+Opcode.fromOp = function fromOp(op) {
+  return new Opcode(op);
+};
+
+/**
+ * Instantiate a pushdata opcode from
+ * a buffer (will encode minimaldata).
+ * @param {Buffer} data
+ * @returns {Opcode}
+ */
+
+Opcode.fromData = function fromData(data) {
+  if (data.length === 0)
+    return new Opcode(opcodes.OP_0);
+
+  if (data.length === 1) {
+    if (data[0] >= 1 && data[0] <= 16)
+      return new Opcode(data[0] + 0x50);
+
+    if (data[0] === 0x81)
+      return new Opcode(opcodes.OP_1NEGATE);
+  }
+
+  return Opcode.fromPush(data);
+};
+
+/**
+ * Instantiate a pushdata opcode from a
+ * buffer (this differs from fromData in
+ * that it will _always_ be a pushdata op).
+ * @param {Buffer} data
+ * @returns {Opcode}
+ */
+
+Opcode.fromPush = function fromPush(data) {
+  if (data.length <= 0x4b)
+    return new Opcode(data.length, data);
+
+  if (data.length <= 0xff)
+    return new Opcode(opcodes.OP_PUSHDATA1, data);
+
+  if (data.length <= 0xffff)
+    return new Opcode(opcodes.OP_PUSHDATA2, data);
+
+  if (data.length <= 0xffffffff)
+    return new Opcode(opcodes.OP_PUSHDATA4, data);
+
+  throw new Error('Pushdata size too large.');
+};
+
+/**
+ * Instantiate an opcode from a Number.
+ * @param {Number|BN} num
+ * @returns {Opcode}
+ */
+
+Opcode.fromNumber = function fromNumber(num) {
+  return Opcode.fromData(bcoin.script.array(num));
+};
+
+/**
+ * Instantiate an opcode from a small number.
+ * @param {Number} num
+ * @returns {Opcode}
+ */
+
+Opcode.fromSmall = function fromSmall(num) {
+  assert(utils.isNumber(num) && num >= 0 && num <= 16);
+  return new Opcode(num === 0 ? 0 : num + 0x50);
+};
+
+/**
+ * Instantiate a pushdata opcode from a string.
+ * @param {String} data
+ * @returns {Opcode}
+ */
+
+Opcode.fromString = function fromString(data, enc) {
+  if (typeof data === 'string')
+    data = new Buffer(data, enc);
+
+  return Opcode.fromData(data);
+};
+
+/**
+ * Instantiate a pushdata opcode from anything.
+ * @param {String|Buffer|Number|BN|Opcode} data
+ * @returns {Opcode}
+ */
+
+Opcode.from = function from(data) {
+  if (data instanceof Opcode)
+    return data;
+
+  if (typeof data === 'number')
+    return Opcode.fromOp(data);
+
+  if (Buffer.isBuffer(data))
+    return Opcode.fromData(data);
+
+  if (typeof data === 'string')
+    return Opcode.fromString(data, 'utf8');
+
+  if (bn.isBN(data))
+    return Opcode.fromNumber(data);
+
+  assert(false, 'Bad data for opcode.');
+};
+
+/**
+ * Test whether an object an Opcode.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+Opcode.isOpcode = function isOpcode(obj) {
+  return obj
+    && typeof obj.value === 'number'
+    && (Buffer.isBuffer(obj.data) || obj.data === null);
+};
+
+/*
+ * Expose
+ */
+
+module.exports = Opcode;
diff --git a/lib/bcoin/script/program.js b/lib/bcoin/script/program.js
new file mode 100644
index 00000000..733b5229
--- /dev/null
+++ b/lib/bcoin/script/program.js
@@ -0,0 +1,109 @@
+/*!
+ * script.js - script interpreter for bcoin
+ * Copyright (c) 2014-2015, Fedor Indutny (MIT License)
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var constants = bcoin.constants;
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var opcodes = constants.opcodes;
+var scriptTypes = constants.scriptTypes;
+
+/**
+ * Witness Program
+ * @constructor
+ * @param {Number} version
+ * @param {Buffer} data
+ * @property {Number} version - Ranges from 0 to 16.
+ * @property {String|null} type - Null if malformed. `unknown` if unknown
+ * version (treated as anyone-can-spend). Otherwise one of `witnesspubkeyhash`
+ * or `witnessscripthash`.
+ * @property {Buffer} data - The hash (for now).
+ */
+
+function Program(version, data) {
+  if (!(this instanceof Program))
+    return new Program(version, data);
+
+  assert(utils.isNumber(version));
+  assert(Buffer.isBuffer(data));
+  assert(version >= 0 && version <= 16);
+  assert(data.length >= 2 && data.length <= 40);
+
+  this.version = version;
+  this.data = data;
+}
+
+/**
+ * Get the witness program type.
+ * @returns {ScriptType}
+ */
+
+Program.prototype.getType = function getType() {
+  if (this.version === 0) {
+    if (this.data.length === 20)
+      return scriptTypes.WITNESSPUBKEYHASH;
+
+    if (this.data.length === 32)
+      return scriptTypes.WITNESSSCRIPTHASH;
+
+    // Fail on bad version=0
+    return scriptTypes.WITNESSMALFORMED;
+  }
+
+  if (this.version === 1) {
+    if (this.data.length === 32)
+      return scriptTypes.WITNESSMASTHASH;
+
+    // Fail on bad version=1
+    return scriptTypes.WITNESSMALFORMED;
+  }
+
+  // No interpretation of script (anyone can spend)
+  return scriptTypes.NONSTANDARD;
+};
+
+/**
+ * Test whether the program is either
+ * an unknown version or malformed.
+ * @returns {Boolean}
+ */
+
+Program.prototype.isUnknown = function isUnknown() {
+  var type = this.getType();
+  return type === scriptTypes.WITNESSMALFORMED
+    || type === scriptTypes.NONSTANDARD;
+};
+
+/**
+ * Test whether the program is malformed.
+ * @returns {Boolean}
+ */
+
+Program.prototype.isMalformed = function isMalformed() {
+  return this.getType() === scriptTypes.WITNESSMALFORMED;
+};
+
+/**
+ * Inspect the program.
+ * @returns {String}
+ */
+
+Program.prototype.inspect = function inspect() {
+  return '<Program:'
+    + ' version=' + this.version
+    + ' data=' + this.data.toString('hex')
+    + ' type=' + constants.scriptTypesByVal[this.getType()].toLowerCase()
+    + '>';
+};
+
+/*
+ * Expose
+ */
+
+module.exports = Program;
diff --git a/lib/bcoin/primitives/script.js b/lib/bcoin/script/script.js
similarity index 76%
rename from lib/bcoin/primitives/script.js
rename to lib/bcoin/script/script.js
index 24ccd962..f73fbcdf 100644
--- a/lib/bcoin/primitives/script.js
+++ b/lib/bcoin/script/script.js
@@ -20,1111 +20,9 @@ var STACK_FALSE = new Buffer([]);
 var STACK_NEGATE = new Buffer([0x81]);
 var ScriptError = bcoin.errors.ScriptError;
 var scriptTypes = constants.scriptTypes;
-
-/**
- * Refers to the witness field of segregated witness transactions.
- * @exports Witness
- * @constructor
- * @param {Buffer[]|NakedWitness} items - Array of
- * stack items.
- * @property {Buffer[]} items
- * @property {Script?} redeem
- * @property {Number} length
- */
-
-function Witness(options) {
-  if (!(this instanceof Witness))
-    return new Witness(options);
-
-  this.items = [];
-
-  if (options)
-    this.fromOptions(options);
-}
-
-Witness.prototype.__defineGetter__('length', function() {
-  return this.items.length;
-});
-
-Witness.prototype.__defineSetter__('length', function(length) {
-  return this.items.length = length;
-});
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-Witness.prototype.fromOptions = function fromOptions(options) {
-  var items;
-
-  assert(options, 'Witness data is required.');
-
-  items = options.items;
-
-  if (!items)
-    items = options;
-
-  if (items)
-    this.fromArray(items);
-
-  return this;
-};
-
-/**
- * Instantiate witness from options.
- * @param {Object} options
- * @returns {Witness}
- */
-
-Witness.fromOptions = function fromOptions(options) {
-  return new Witness().fromOptions(options);
-};
-
-/**
- * Convert witness to an array of buffers.
- * @returns {Buffer[]}
- */
-
-Witness.prototype.toArray = function toArray() {
-  return this.items.slice();
-};
-
-/**
- * Inject properties from an array of buffers.
- * @private
- * @param {Buffer[]} items
- */
-
-Witness.prototype.fromArray = function fromArray(items) {
-  assert(Array.isArray(items));
-  this.items = items;
-  return this;
-};
-
-/**
- * Insantiate witness from an array of buffers.
- * @param {Buffer[]} items
- * @returns {Witness}
- */
-
-Witness.fromArray = function fromArray(items) {
-  return new Witness().fromArray(items);
-};
-
-/**
- * Inspect a Witness object.
- * @returns {String} Human-readable script.
- */
-
-Witness.prototype.inspect = function inspect() {
-  return '<Witness: ' + this.toString() + '>';
-};
-
-/**
- * Convert a Witness object to a String.
- * @returns {String} Human-readable script.
- */
-
-Witness.prototype.toString = function toString() {
-  return Witness.format(this.items);
-};
-
-/**
- * Format the witness object as bitcoind asm.
- * @param {Boolean?} decode - Attempt to decode hash types.
- * @returns {String} Human-readable script.
- */
-
-Witness.prototype.toASM = function toASM(decode) {
-  return Script.formatASM(Script.parseArray(this.items), decode);
-};
-
-/**
- * Clone the witness object. Note that the raw
- * encoded witness data will be lost. This is
- * because the function assumes you are going
- * to be altering the stack items by hand.
- * @returns {Witness} A clone of the current witness object.
- */
-
-Witness.prototype.clone = function clone() {
-  return new Witness(this.items.slice());
-};
-
-/**
- * Convert the Witness to a Stack object.
- * This is usually done before executing
- * a witness program.
- * @returns {Stack}
- */
-
-Witness.prototype.toStack = function toStack() {
-  return new Stack(this.items.slice());
-};
-
-/**
- * "Guess" the type of the witness.
- * This method is not 100% reliable.
- * @returns {ScriptType}
- */
-
-Witness.prototype.getInputType = function getInputType() {
-  if (this.isPubkeyhashInput())
-    return scriptTypes.WITNESSPUBKEYHASH;
-
-  if (this.isScripthashInput())
-    return scriptTypes.WITNESSSCRIPTHASH;
-
-  return scriptTypes.NONSTANDARD;
-};
-
-/**
- * "Guess" the address of the witness.
- * This method is not 100% reliable.
- * @returns {Address|null}
- */
-
-Witness.prototype.getInputAddress = function getInputAddress() {
-  return bcoin.address.fromWitness(this);
-};
-
-/**
- * "Test" whether the witness is a pubkey input.
- * Always returns false.
- * @returns {Boolean}
- */
-
-Witness.prototype.isPubkeyInput = function isPubkeyInput() {
-  return false;
-};
-
-/**
- * "Guess" whether the witness is a pubkeyhash input.
- * This method is not 100% reliable.
- * @returns {Boolean}
- */
-
-Witness.prototype.isPubkeyhashInput = function isPubkeyhashInput() {
-  return this.items.length === 2
-    && Script.isSignatureEncoding(this.items[0])
-    && Script.isKeyEncoding(this.items[1]);
-};
-
-/**
- * "Test" whether the witness is a multisig input.
- * Always returns false.
- * @returns {Boolean}
- */
-
-Witness.prototype.isMultisigInput = function isMultisigInput() {
-  return false;
-};
-
-/**
- * "Guess" whether the witness is a scripthash input.
- * This method is not 100% reliable.
- * @returns {Boolean}
- */
-
-Witness.prototype.isScripthashInput = function isScripthashInput() {
-  return this.items.length > 0 && !this.isPubkeyhashInput();
-};
-
-/**
- * "Guess" whether the witness is an unknown/non-standard type.
- * This method is not 100% reliable.
- * @returns {Boolean}
- */
-
-Witness.prototype.isUnknownInput = function isUnknownInput() {
-  return this.getInputType() === scriptTypes.NONSTANDARD;
-};
-
-/**
- * Test the witness against a bloom filter.
- * @param {Bloom} filter
- * @returns {Boolean}
- */
-
-Witness.prototype.test = function test(filter) {
-  var i, chunk;
-
-  for (i = 0; i < this.items.length; i++) {
-    chunk = this.items[i];
-
-    if (chunk.length === 0)
-      continue;
-
-    if (filter.test(chunk))
-      return true;
-  }
-
-  return false;
-};
-
-/**
- * Grab and deserialize the redeem script from the witness.
- * @returns {Script} Redeem script.
- */
-
-Witness.prototype.getRedeem = function getRedeem() {
-  var redeem = this.items[this.items.length - 1];
-
-  if (!redeem)
-    return;
-
-  return new Script(redeem);
-};
-
-/**
- * Does nothing currently.
- */
-
-Witness.prototype.compile = function compile() {
-  // NOP
-};
-
-/**
- * Find a data element in a witness.
- * @param {Buffer} data - Data element to match against.
- * @returns {Number} Index (`-1` if not present).
- */
-
-Witness.prototype.indexOf = function indexOf(data) {
-  return utils.indexOf(this.items, data);
-};
-
-/**
- * Encode the witness to a Buffer.
- * @param {String} enc - Encoding, either `'hex'` or `null`.
- * @returns {Buffer|String} Serialized script.
- */
-
-Witness.prototype.toRaw = function toRaw(writer) {
-  var p = bcoin.writer(writer);
-  var i;
-
-  p.writeVarint(this.items.length);
-
-  for (i = 0; i < this.items.length; i++)
-    p.writeVarBytes(this.items[i]);
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Convert witness to a hex string.
- * @returns {String}
- */
-
-Witness.prototype.toJSON = function toJSON() {
-  return this.toRaw().toString('hex');
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {String} json
- */
-
-Witness.prototype.fromJSON = function fromJSON(json) {
-  assert(typeof json === 'string');
-  return this.fromRaw(new Buffer(json, 'hex'));
-};
-
-/**
- * Insantiate witness from a hex string.
- * @param {String} json
- * @returns {Witness}
- */
-
-Witness.fromJSON = function fromJSON(json) {
-  return new Witness().fromJSON(json);
-};
-
-/**
- * Unshift an item onto the witness vector.
- * @param {Number|String|Buffer|BN} data
- * @returns {Number}
- */
-
-Witness.prototype.unshift = function unshift(data) {
-  return this.items.unshift(Witness.encodeItem(data));
-};
-
-/**
- * Push an item onto the witness vector.
- * @param {Number|String|Buffer|BN} data
- * @returns {Number}
- */
-
-Witness.prototype.push = function push(data) {
-  return this.items.push(Witness.encodeItem(data));
-};
-
-/**
- * Shift an item off the witness vector.
- * @returns {Buffer}
- */
-
-Witness.prototype.shift = function shift() {
-  return this.items.shift();
-};
-
-/**
- * Shift an item off the witness vector.
- * @returns {Buffer}
- */
-
-Witness.prototype.pop = function push(data) {
-  return this.items.pop();
-};
-
-/**
- * Remove an item from the witness vector.
- * @param {Number} index
- * @returns {Buffer}
- */
-
-Witness.prototype.remove = function remove(i) {
-  return this.items.splice(i, 1)[0];
-};
-
-/**
- * Insert an item into the witness vector.
- * @param {Number} index
- * @param {Number|String|Buffer|BN} data
- */
-
-Witness.prototype.insert = function insert(i, data) {
-  assert(i <= this.items.length, 'Index out of bounds.');
-  this.items.splice(i, 0, Witness.encodeItem(data))[0];
-};
-
-/**
- * Get an item from the witness vector.
- * @param {Number} index
- * @returns {Buffer}
- */
-
-Witness.prototype.get = function get(i) {
-  return this.items[i];
-};
-
-/**
- * Get a small int (0-16) from the witness vector.
- * @param {Number} index
- * @returns {Number} `-1` on non-existent.
- */
-
-Witness.prototype.getSmall = function getSmall(i) {
-  var item = this.items[i];
-  if (!item || item.length > 1)
-    return -1;
-  if (item.length === 0)
-    return 0;
-  if (!(item[0] >= 1 && item[1] <= 16))
-    return -1;
-  return item[0];
-};
-
-/**
- * Get a number from the witness vector.
- * @param {Number} index
- * @returns {BN}
- */
-
-Witness.prototype.getNumber = function getNumber(i) {
-  var item = this.items[i];
-  if (!item || item.length > 5)
-    return;
-  return Script.num(item, constants.flags.VERIFY_NONE, 5);
-};
-
-/**
- * Get a string from the witness vector.
- * @param {Number} index
- * @returns {String}
- */
-
-Witness.prototype.getString = function getString(i) {
-  var item = this.items[i];
-  if (!item)
-    return;
-  return item.toString('utf8');
-};
-
-/**
- * Clear the witness items.
- */
-
-Witness.prototype.clear = function clear() {
-  this.items.length = 0;
-};
-
-/**
- * Set an item in the witness vector.
- * @param {Number} index
- * @param {Number|String|Buffer|BN} data
- */
-
-Witness.prototype.set = function set(i, data) {
-  assert(i <= this.items.length, 'Index out of bounds.');
-  this.items[i] = Witness.encodeItem(data);
-};
-
-/**
- * Encode a witness item.
- * @param {Number|String|Buffer|BN} data
- * @returns {Buffer}
- */
-
-Witness.encodeItem = function encodeItem(data) {
-  if (data instanceof Opcode)
-    data = data.data || data.value;
-
-  if (typeof data === 'number') {
-    if (data === opcodes.OP_1NEGATE)
-      return STACK_NEGATE;
-
-    if (data === opcodes.OP_0)
-      return STACK_FALSE;
-
-    if (data >= opcodes.OP_1 && data <= opcodes.OP_16)
-      return new Buffer([data - 0x50]);
-
-    throw new Error('Non-push opcode in witness.');
-  }
-
-  if (bn.isBN(data))
-    return Script.array(data);
-
-  if (typeof data === 'string')
-    return new Buffer(data, 'utf8');
-
-  return data;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- */
-
-Witness.prototype.fromRaw = function fromRaw(data) {
-  var p = bcoin.reader(data);
-  var chunkCount = p.readVarint();
-  var i;
-
-  for (i = 0; i < chunkCount; i++)
-    this.items.push(p.readVarBytes());
-
-  return this;
-};
-
-/**
- * Create a Witness from a serialized buffer.
- * @param {Buffer|String} data - Serialized witness.
- * @param {String?} enc - Either `"hex"` or `null`.
- * @returns {Witness}
- */
-
-Witness.fromRaw = function fromRaw(data, enc) {
-  if (typeof data === 'string')
-    data = new Buffer(data, enc);
-  return new Witness().fromRaw(data);
-};
-
-/**
- * Inject items from string.
- * @private
- * @param {String|String[]} items
- */
-
-Witness.prototype.fromString = function fromString(items) {
-  var i;
-
-  if (!Array.isArray(items)) {
-    assert(typeof items === 'string');
-
-    items = items.trim();
-
-    if (items.length === 0)
-      return this;
-
-    items = items.split(/\s+/);
-  }
-
-  for (i = 0; i < items.length; i++)
-    this.items.push(new Buffer(items[i], 'hex'));
-
-  return this;
-};
-
-/**
- * Parse a test script/array
- * string into a witness object. _Must_
- * contain only stack items (no non-push
- * opcodes).
- * @param {String|String[]} items - Script string.
- * @returns {Witness}
- * @throws Parse error.
- */
-
-Witness.fromString = function fromString(items) {
-  return new Witness().fromString(items);
-};
-
-/**
- * Format script code into a human readable-string.
- * @param {Array} code
- * @returns {String} Human-readable string.
- */
-
-Witness.format = function format(items) {
-  var out = [];
-  var i;
-
-  for (i = 0; i < items.length; i++)
-    out.push(items[i].toString('hex'));
-
-  return out.join(' ');
-};
-
-/**
- * Test an object to see if it is a Witness.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-Witness.isWitness = function isWitness(obj) {
-  return obj
-    && Array.isArray(obj.items)
-    && typeof obj.toStack === 'function';
-};
-
-/**
- * Represents the stack of a Script during execution.
- * @exports Stack
- * @constructor
- * @param {Buffer[]?} items - Stack items.
- * @property {Buffer[]} items - Stack items.
- * @property {Number} length - Size of stack.
- */
-
-function Stack(items) {
-  if (!(this instanceof Stack))
-    return new Stack(items);
-
-  this.items = items || [];
-}
-
-Stack.prototype.__defineGetter__('length', function() {
-  return this.items.length;
-});
-
-Stack.prototype.__defineSetter__('length', function(length) {
-  return this.items.length = length;
-});
-
-/**
- * Inspect the stack.
- * @returns {String} Human-readable stack.
- */
-
-Stack.prototype.inspect = function inspect() {
-  return '<Stack: ' + this.toString() + '>';
-};
-
-/**
- * Convert the stack to a string.
- * @returns {String} Human-readable stack.
- */
-
-Stack.prototype.toString = function toString() {
-  return Witness.format(this.items);
-};
-
-/**
- * Format the stack as bitcoind asm.
- * @param {Boolean?} decode - Attempt to decode hash types.
- * @returns {String} Human-readable script.
- */
-
-Stack.prototype.toASM = function toASM(decode) {
-  return Script.formatASM(this.items, decode);
-};
-
-/**
- * Pop the redeem script off the stack and deserialize it.
- * @returns {Script|null} The redeem script.
- */
-
-Stack.prototype.getRedeem = function getRedeem() {
-  var redeem = this.items[this.items.length - 1];
-  if (!redeem)
-    return;
-  return new Script(redeem);
-};
-
-/**
- * Clone the stack.
- * @returns {Stack} Cloned stack.
- */
-
-Stack.prototype.clone = function clone() {
-  return new Stack(this.items.slice());
-};
-
-/**
- * Get total size of the stack, including the alt stack.
- * @param {Array} alt - Alt stack.
- * @returns {Number}
- */
-
-Stack.prototype.getSize = function getSize(alt) {
-  return this.items.length + alt.length;
-};
-
-/**
- * Push item onto stack.
- * @see Array#push
- * @param {Buffer} item
- * @returns {Number} Stack size.
- */
-
-Stack.prototype.push = function push(item) {
-  return this.items.push(item);
-};
-
-/**
- * Unshift item from stack.
- * @see Array#unshift
- * @param {Buffer} item
- * @returns {Number}
- */
-
-Stack.prototype.unshift = function unshift(item) {
-  return this.items.unshift(item);
-};
-
-/**
- * Slice out part of the stack items.
- * @param {Number} start
- * @param {Number} end
- * @see Array#slice
- * @returns {Buffer[]}
- */
-
-Stack.prototype.slice = function slice(start, end) {
-  return this.items.slice(start, end);
-};
-
-/**
- * Splice stack items.
- * @see Array#splice
- * @param {Number} index
- * @param {Number} remove
- * @param {Buffer?} insert
- * @returns {Buffer[]}
- */
-
-Stack.prototype.splice = function splice(i, remove, insert) {
-  if (insert === undefined)
-    return this.items.splice(i, remove);
-  return this.items.splice(i, remove, insert);
-};
-
-/**
- * Pop a stack item.
- * @see Array#pop
- * @returns {Buffer|null}
- */
-
-Stack.prototype.pop = function pop() {
-  return this.items.pop();
-};
-
-/**
- * Shift a stack item.
- * @see Array#shift
- * @returns {Buffer|null}
- */
-
-Stack.prototype.shift = function shift() {
-  return this.items.shift();
-};
-
-/**
- * Get a stack item by index.
- * @param {Number} index
- * @returns {Buffer|null}
- */
-
-Stack.prototype.get = function get(i) {
-  return this.items[i];
-};
-
-/**
- * Get a stack item relative to
- * the top of the stack.
- * @example
- * stack.top(-1);
- * @param {Number} index
- * @returns {Buffer|null}
- */
-
-Stack.prototype.top = function top(i) {
-  return this.items[this.items.length + i];
-};
-
-/**
- * Clear the stack.
- */
-
-Stack.prototype.clear = function clear() {
-  this.items.length = 0;
-};
-
-/**
- * Set stack item at index.
- * @param {Number} index
- * @param {Buffer} value
- * @returns {Buffer}
- */
-
-Stack.prototype.set = function set(i, value) {
-  return this.items[i] = value;
-};
-
-/**
- * Swap stack values.
- * @private
- * @param {Number} i1 - Index 1.
- * @param {Number} i2 - Index 2.
- */
-
-Stack.prototype._swap = function _swap(i1, i2) {
-  var v1, v2;
-
-  i1 = this.items.length + i1;
-  i2 = this.items.length + i2;
-
-  v1 = this.items[i1];
-  v2 = this.items[i2];
-
-  this.items[i1] = v2;
-  this.items[i2] = v1;
-};
-
-/**
- * Perform the OP_TOALTSTACK operation.
- * @param {Array} alt - Alt stack.
- * @throws {ScriptError}
- */
-
-Stack.prototype.toalt = function toalt(alt) {
-  if (this.length === 0)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_TOALTSTACK);
-
-  alt.push(this.pop());
-};
-
-/**
- * Perform the OP_FROMALTSTACK operation.
- * @param {Array} alt - Alt stack.
- * @throws {ScriptError}
- */
-
-Stack.prototype.fromalt = function fromalt(alt) {
-  if (alt.length === 0)
-    throw new ScriptError('INVALID_ALTSTACK_OPERATION', opcodes.OP_FROMALTSTACK);
-
-  this.push(alt.pop());
-};
-
-/**
- * Perform the OP_IFDUP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.ifdup = function ifdup() {
-  if (this.length === 0)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_IFDUP);
-
-  if (Script.bool(this.top(-1)))
-    this.push(this.top(-1));
-};
-
-/**
- * Perform the OP_DEPTH operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.depth = function depth() {
-  this.push(Script.array(this.length));
-};
-
-/**
- * Perform the OP_DROP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.drop = function drop() {
-  if (this.length === 0)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_DROP);
-
-  this.pop();
-};
-
-/**
- * Perform the OP_DUP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.dup = function dup() {
-  if (this.length === 0)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_DUP);
-
-  this.push(this.top(-1));
-};
-
-/**
- * Perform the OP_NIP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.nip = function nip() {
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_NIP);
-
-  this.splice(this.length - 2, 1);
-};
-
-/**
- * Perform the OP_OVER operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.over = function over() {
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_OVER);
-
-  this.push(this.top(-2));
-};
-
-/**
- * Perform the OP_PICK operation.
- * @param {VerifyFlags} flags
- * @throws {ScriptError}
- */
-
-Stack.prototype.pick = function pick(flags) {
-  return this._pickroll(opcodes.OP_PICK, flags);
-};
-
-/**
- * Perform the OP_ROLL operation.
- * @param {VerifyFlags} flags
- * @throws {ScriptError}
- */
-
-Stack.prototype.roll = function roll(flags) {
-  return this._pickroll(opcodes.OP_ROLL, flags);
-};
-
-/**
- * Perform a pick or roll.
- * @private
- * @param {Number} op
- * @param {VerifyFlags} flags
- * @throws {ScriptError}
- */
-
-Stack.prototype._pickroll = function pickroll(op, flags) {
-  var val, n;
-
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', op);
-
-  val = this.pop();
-  n = Script.num(val, flags).toNumber();
-
-  if (n < 0 || n >= this.length)
-    throw new ScriptError('INVALID_STACK_OPERATION', op);
-
-  val = this.top(-n - 1);
-
-  if (op === opcodes.OP_ROLL)
-    this.splice(this.length - n - 1, 1);
-
-  this.push(val);
-};
-
-/**
- * Perform the OP_ROT operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.rot = function rot() {
-  if (this.length < 3)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_ROT);
-
-  this._swap(-3, -2);
-  this._swap(-2, -1);
-};
-
-/**
- * Perform the OP_SWAP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.swap = function swap() {
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_SWAP);
-
-  this._swap(-2, -1);
-};
-
-/**
- * Perform the OP_TUCK operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.tuck = function tuck() {
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_TUCK);
-
-  this.splice(this.length - 2, 0, this.top(-1));
-};
-
-/**
- * Perform the OP_2DROP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.drop2 = function drop2() {
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2DROP);
-
-  this.pop();
-  this.pop();
-};
-
-/**
- * Perform the OP_2DUP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.dup2 = function dup2() {
-  var v1, v2;
-
-  if (this.length < 2)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2DUP);
-
-  v1 = this.top(-2);
-  v2 = this.top(-1);
-
-  this.push(v1);
-  this.push(v2);
-};
-
-/**
- * Perform the OP_3DUP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.dup3 = function dup3() {
-  var v1, v2, v3;
-
-  if (this.length < 3)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_3DUP);
-
-  v1 = this.top(-3);
-  v2 = this.top(-2);
-  v3 = this.top(-1);
-
-  this.push(v1);
-  this.push(v2);
-  this.push(v3);
-};
-
-/**
- * Perform the OP_2OVER operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.over2 = function over2() {
-  var v1, v2;
-
-  if (this.length < 4)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2OVER);
-
-  v1 = this.top(-4);
-  v2 = this.top(-3);
-
-  this.push(v1);
-  this.push(v2);
-};
-
-/**
- * Perform the OP_2ROT operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.rot2 = function rot2() {
-  var v1, v2;
-
-  if (this.length < 6)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2ROT);
-
-  v1 = this.top(-6);
-  v2 = this.top(-5);
-
-  this.splice(this.length - 6, 2);
-  this.push(v1);
-  this.push(v2);
-};
-
-/**
- * Perform the OP_2SWAP operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.swap2 = function swap2() {
-  if (this.length < 4)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2SWAP);
-
-  this._swap(-4, -2);
-  this._swap(-3, -1);
-};
-
-/**
- * Perform the OP_SIZE operation.
- * @throws {ScriptError}
- */
-
-Stack.prototype.size = function size() {
-  if (this.length < 1)
-    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_SIZE);
-
-  this.push(Script.array(this.top(-1).length));
-};
-
-/**
- * Test an object to see if it is a Stack.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-Stack.isStack = function isStack(obj) {
-  return obj && Array.isArray(obj.items) && typeof obj.swap2 === 'function';
-};
+var Program = require('./program');
+var Opcode = require('./opcode');
+var Stack = require('./stack');
 
 /**
  * Represents a input or output script.
@@ -4709,249 +3607,6 @@ Script.isScript = function isScript(obj) {
     && typeof obj.getSubscript === 'function';
 };
 
-/**
- * A simple struct which contains
- * an opcode and pushdata buffer.
- * @exports Opcode
- * @constructor
- * @param {Number} value - Opcode.
- * @param {Buffer?} data - Pushdata buffer.
- * @property {Number} value
- * @property {Buffer|null} data
- */
-
-function Opcode(value, data) {
-  if (!(this instanceof Opcode))
-    return new Opcode(value, data);
-
-  this.value = value;
-  this.data = data || null;
-}
-
-/**
- * Encode the opcode.
- * @returns {Buffer}
- */
-
-Opcode.prototype.toRaw = function toRaw(writer) {
-  return Script.encode([this], writer);
-};
-
-/**
- * Instantiate an opcode from a number opcode.
- * @param {Number} op
- * @returns {Opcode}
- */
-
-Opcode.fromOp = function fromOp(op) {
-  return new Opcode(op);
-};
-
-/**
- * Instantiate a pushdata opcode from
- * a buffer (will encode minimaldata).
- * @param {Buffer} data
- * @returns {Opcode}
- */
-
-Opcode.fromData = function fromData(data) {
-  if (data.length === 0)
-    return new Opcode(opcodes.OP_0);
-
-  if (data.length === 1) {
-    if (data[0] >= 1 && data[0] <= 16)
-      return new Opcode(data[0] + 0x50);
-
-    if (data[0] === 0x81)
-      return new Opcode(opcodes.OP_1NEGATE);
-  }
-
-  return Opcode.fromPush(data);
-};
-
-/**
- * Instantiate a pushdata opcode from a
- * buffer (this differs from fromData in
- * that it will _always_ be a pushdata op).
- * @param {Buffer} data
- * @returns {Opcode}
- */
-
-Opcode.fromPush = function fromPush(data) {
-  if (data.length <= 0x4b)
-    return new Opcode(data.length, data);
-
-  if (data.length <= 0xff)
-    return new Opcode(opcodes.OP_PUSHDATA1, data);
-
-  if (data.length <= 0xffff)
-    return new Opcode(opcodes.OP_PUSHDATA2, data);
-
-  if (data.length <= 0xffffffff)
-    return new Opcode(opcodes.OP_PUSHDATA4, data);
-
-  throw new Error('Pushdata size too large.');
-};
-
-/**
- * Instantiate an opcode from a Number.
- * @param {Number|BN} num
- * @returns {Opcode}
- */
-
-Opcode.fromNumber = function fromNumber(num) {
-  return Opcode.fromData(Script.array(num));
-};
-
-/**
- * Instantiate an opcode from a small number.
- * @param {Number} num
- * @returns {Opcode}
- */
-
-Opcode.fromSmall = function fromSmall(num) {
-  assert(utils.isNumber(num) && num >= 0 && num <= 16);
-  return new Opcode(num === 0 ? 0 : num + 0x50);
-};
-
-/**
- * Instantiate a pushdata opcode from a string.
- * @param {String} data
- * @returns {Opcode}
- */
-
-Opcode.fromString = function fromString(data, enc) {
-  if (typeof data === 'string')
-    data = new Buffer(data, enc);
-
-  return Opcode.fromData(data);
-};
-
-/**
- * Instantiate a pushdata opcode from anything.
- * @param {String|Buffer|Number|BN|Opcode} data
- * @returns {Opcode}
- */
-
-Opcode.from = function from(data) {
-  if (data instanceof Opcode)
-    return data;
-
-  if (typeof data === 'number')
-    return Opcode.fromOp(data);
-
-  if (Buffer.isBuffer(data))
-    return Opcode.fromData(data);
-
-  if (typeof data === 'string')
-    return Opcode.fromString(data, 'utf8');
-
-  if (bn.isBN(data))
-    return Opcode.fromNumber(data);
-
-  assert(false, 'Bad data for opcode.');
-};
-
-/**
- * Test whether an object an Opcode.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-Opcode.isOpcode = function isOpcode(obj) {
-  return obj
-    && typeof obj.value === 'number'
-    && (Buffer.isBuffer(obj.data) || obj.data === null);
-};
-
-/**
- * Witness Program
- * @constructor
- * @param {Number} version
- * @param {Buffer} data
- * @property {Number} version - Ranges from 0 to 16.
- * @property {String|null} type - Null if malformed. `unknown` if unknown
- * version (treated as anyone-can-spend). Otherwise one of `witnesspubkeyhash`
- * or `witnessscripthash`.
- * @property {Buffer} data - The hash (for now).
- */
-
-function Program(version, data) {
-  if (!(this instanceof Program))
-    return new Program(version, data);
-
-  assert(utils.isNumber(version));
-  assert(Buffer.isBuffer(data));
-  assert(version >= 0 && version <= 16);
-  assert(data.length >= 2 && data.length <= 40);
-
-  this.version = version;
-  this.data = data;
-}
-
-/**
- * Get the witness program type.
- * @returns {ScriptType}
- */
-
-Program.prototype.getType = function getType() {
-  if (this.version === 0) {
-    if (this.data.length === 20)
-      return scriptTypes.WITNESSPUBKEYHASH;
-
-    if (this.data.length === 32)
-      return scriptTypes.WITNESSSCRIPTHASH;
-
-    // Fail on bad version=0
-    return scriptTypes.WITNESSMALFORMED;
-  }
-
-  if (this.version === 1) {
-    if (this.data.length === 32)
-      return scriptTypes.WITNESSMASTHASH;
-
-    // Fail on bad version=1
-    return scriptTypes.WITNESSMALFORMED;
-  }
-
-  // No interpretation of script (anyone can spend)
-  return scriptTypes.NONSTANDARD;
-};
-
-/**
- * Test whether the program is either
- * an unknown version or malformed.
- * @returns {Boolean}
- */
-
-Program.prototype.isUnknown = function isUnknown() {
-  var type = this.getType();
-  return type === scriptTypes.WITNESSMALFORMED
-    || type === scriptTypes.NONSTANDARD;
-};
-
-/**
- * Test whether the program is malformed.
- * @returns {Boolean}
- */
-
-Program.prototype.isMalformed = function isMalformed() {
-  return this.getType() === scriptTypes.WITNESSMALFORMED;
-};
-
-/**
- * Inspect the program.
- * @returns {String}
- */
-
-Program.prototype.inspect = function inspect() {
-  return '<Program:'
-    + ' version=' + this.version
-    + ' data=' + this.data.toString('hex')
-    + ' type=' + constants.scriptTypesByVal[this.getType()].toLowerCase()
-    + '>';
-};
-
 /*
  * Expose
  */
@@ -4964,9 +3619,4 @@ exports.types = scriptTypes;
 exports.typesByVal = constants.scriptTypesByVal;
 exports.flags = constants.flags;
 
-exports.Script = Script;
-exports.Opcode = Opcode;
-exports.Stack = Stack;
-exports.Witness = Witness;
-
 module.exports = exports;
diff --git a/lib/bcoin/sigcache.js b/lib/bcoin/script/sigcache.js
similarity index 98%
rename from lib/bcoin/sigcache.js
rename to lib/bcoin/script/sigcache.js
index 3d12729e..0df6e0e0 100644
--- a/lib/bcoin/sigcache.js
+++ b/lib/bcoin/script/sigcache.js
@@ -6,7 +6,7 @@
 
 'use strict';
 
-var bcoin = require('./env');
+var bcoin = require('../env');
 var utils = bcoin.utils;
 var assert = utils.assert;
 
diff --git a/lib/bcoin/script/stack.js b/lib/bcoin/script/stack.js
new file mode 100644
index 00000000..f8aa648c
--- /dev/null
+++ b/lib/bcoin/script/stack.js
@@ -0,0 +1,537 @@
+/*!
+ * script.js - script interpreter for bcoin
+ * Copyright (c) 2014-2015, Fedor Indutny (MIT License)
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var constants = bcoin.constants;
+var opcodes = constants.opcodes;
+var ScriptError = bcoin.errors.ScriptError;
+
+/**
+ * Represents the stack of a Script during execution.
+ * @exports Stack
+ * @constructor
+ * @param {Buffer[]?} items - Stack items.
+ * @property {Buffer[]} items - Stack items.
+ * @property {Number} length - Size of stack.
+ */
+
+function Stack(items) {
+  if (!(this instanceof Stack))
+    return new Stack(items);
+
+  this.items = items || [];
+}
+
+Stack.prototype.__defineGetter__('length', function() {
+  return this.items.length;
+});
+
+Stack.prototype.__defineSetter__('length', function(length) {
+  return this.items.length = length;
+});
+
+/**
+ * Inspect the stack.
+ * @returns {String} Human-readable stack.
+ */
+
+Stack.prototype.inspect = function inspect() {
+  return '<Stack: ' + this.toString() + '>';
+};
+
+/**
+ * Convert the stack to a string.
+ * @returns {String} Human-readable stack.
+ */
+
+Stack.prototype.toString = function toString() {
+  return bcoin.witness.format(this.items);
+};
+
+/**
+ * Format the stack as bitcoind asm.
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable script.
+ */
+
+Stack.prototype.toASM = function toASM(decode) {
+  return bcoin.script.formatASM(this.items, decode);
+};
+
+/**
+ * Pop the redeem script off the stack and deserialize it.
+ * @returns {Script|null} The redeem script.
+ */
+
+Stack.prototype.getRedeem = function getRedeem() {
+  var redeem = this.items[this.items.length - 1];
+  if (!redeem)
+    return;
+  return new bcoin.script(redeem);
+};
+
+/**
+ * Clone the stack.
+ * @returns {Stack} Cloned stack.
+ */
+
+Stack.prototype.clone = function clone() {
+  return new Stack(this.items.slice());
+};
+
+/**
+ * Get total size of the stack, including the alt stack.
+ * @param {Array} alt - Alt stack.
+ * @returns {Number}
+ */
+
+Stack.prototype.getSize = function getSize(alt) {
+  return this.items.length + alt.length;
+};
+
+/**
+ * Push item onto stack.
+ * @see Array#push
+ * @param {Buffer} item
+ * @returns {Number} Stack size.
+ */
+
+Stack.prototype.push = function push(item) {
+  return this.items.push(item);
+};
+
+/**
+ * Unshift item from stack.
+ * @see Array#unshift
+ * @param {Buffer} item
+ * @returns {Number}
+ */
+
+Stack.prototype.unshift = function unshift(item) {
+  return this.items.unshift(item);
+};
+
+/**
+ * Slice out part of the stack items.
+ * @param {Number} start
+ * @param {Number} end
+ * @see Array#slice
+ * @returns {Buffer[]}
+ */
+
+Stack.prototype.slice = function slice(start, end) {
+  return this.items.slice(start, end);
+};
+
+/**
+ * Splice stack items.
+ * @see Array#splice
+ * @param {Number} index
+ * @param {Number} remove
+ * @param {Buffer?} insert
+ * @returns {Buffer[]}
+ */
+
+Stack.prototype.splice = function splice(i, remove, insert) {
+  if (insert === undefined)
+    return this.items.splice(i, remove);
+  return this.items.splice(i, remove, insert);
+};
+
+/**
+ * Pop a stack item.
+ * @see Array#pop
+ * @returns {Buffer|null}
+ */
+
+Stack.prototype.pop = function pop() {
+  return this.items.pop();
+};
+
+/**
+ * Shift a stack item.
+ * @see Array#shift
+ * @returns {Buffer|null}
+ */
+
+Stack.prototype.shift = function shift() {
+  return this.items.shift();
+};
+
+/**
+ * Get a stack item by index.
+ * @param {Number} index
+ * @returns {Buffer|null}
+ */
+
+Stack.prototype.get = function get(i) {
+  return this.items[i];
+};
+
+/**
+ * Get a stack item relative to
+ * the top of the stack.
+ * @example
+ * stack.top(-1);
+ * @param {Number} index
+ * @returns {Buffer|null}
+ */
+
+Stack.prototype.top = function top(i) {
+  return this.items[this.items.length + i];
+};
+
+/**
+ * Clear the stack.
+ */
+
+Stack.prototype.clear = function clear() {
+  this.items.length = 0;
+};
+
+/**
+ * Set stack item at index.
+ * @param {Number} index
+ * @param {Buffer} value
+ * @returns {Buffer}
+ */
+
+Stack.prototype.set = function set(i, value) {
+  return this.items[i] = value;
+};
+
+/**
+ * Swap stack values.
+ * @private
+ * @param {Number} i1 - Index 1.
+ * @param {Number} i2 - Index 2.
+ */
+
+Stack.prototype._swap = function _swap(i1, i2) {
+  var v1, v2;
+
+  i1 = this.items.length + i1;
+  i2 = this.items.length + i2;
+
+  v1 = this.items[i1];
+  v2 = this.items[i2];
+
+  this.items[i1] = v2;
+  this.items[i2] = v1;
+};
+
+/**
+ * Perform the OP_TOALTSTACK operation.
+ * @param {Array} alt - Alt stack.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.toalt = function toalt(alt) {
+  if (this.length === 0)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_TOALTSTACK);
+
+  alt.push(this.pop());
+};
+
+/**
+ * Perform the OP_FROMALTSTACK operation.
+ * @param {Array} alt - Alt stack.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.fromalt = function fromalt(alt) {
+  if (alt.length === 0)
+    throw new ScriptError('INVALID_ALTSTACK_OPERATION', opcodes.OP_FROMALTSTACK);
+
+  this.push(alt.pop());
+};
+
+/**
+ * Perform the OP_IFDUP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.ifdup = function ifdup() {
+  if (this.length === 0)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_IFDUP);
+
+  if (bcoin.script.bool(this.top(-1)))
+    this.push(this.top(-1));
+};
+
+/**
+ * Perform the OP_DEPTH operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.depth = function depth() {
+  this.push(bcoin.script.array(this.length));
+};
+
+/**
+ * Perform the OP_DROP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.drop = function drop() {
+  if (this.length === 0)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_DROP);
+
+  this.pop();
+};
+
+/**
+ * Perform the OP_DUP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.dup = function dup() {
+  if (this.length === 0)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_DUP);
+
+  this.push(this.top(-1));
+};
+
+/**
+ * Perform the OP_NIP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.nip = function nip() {
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_NIP);
+
+  this.splice(this.length - 2, 1);
+};
+
+/**
+ * Perform the OP_OVER operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.over = function over() {
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_OVER);
+
+  this.push(this.top(-2));
+};
+
+/**
+ * Perform the OP_PICK operation.
+ * @param {VerifyFlags} flags
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.pick = function pick(flags) {
+  return this._pickroll(opcodes.OP_PICK, flags);
+};
+
+/**
+ * Perform the OP_ROLL operation.
+ * @param {VerifyFlags} flags
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.roll = function roll(flags) {
+  return this._pickroll(opcodes.OP_ROLL, flags);
+};
+
+/**
+ * Perform a pick or roll.
+ * @private
+ * @param {Number} op
+ * @param {VerifyFlags} flags
+ * @throws {ScriptError}
+ */
+
+Stack.prototype._pickroll = function pickroll(op, flags) {
+  var val, n;
+
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', op);
+
+  val = this.pop();
+  n = bcoin.script.num(val, flags).toNumber();
+
+  if (n < 0 || n >= this.length)
+    throw new ScriptError('INVALID_STACK_OPERATION', op);
+
+  val = this.top(-n - 1);
+
+  if (op === opcodes.OP_ROLL)
+    this.splice(this.length - n - 1, 1);
+
+  this.push(val);
+};
+
+/**
+ * Perform the OP_ROT operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.rot = function rot() {
+  if (this.length < 3)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_ROT);
+
+  this._swap(-3, -2);
+  this._swap(-2, -1);
+};
+
+/**
+ * Perform the OP_SWAP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.swap = function swap() {
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_SWAP);
+
+  this._swap(-2, -1);
+};
+
+/**
+ * Perform the OP_TUCK operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.tuck = function tuck() {
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_TUCK);
+
+  this.splice(this.length - 2, 0, this.top(-1));
+};
+
+/**
+ * Perform the OP_2DROP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.drop2 = function drop2() {
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2DROP);
+
+  this.pop();
+  this.pop();
+};
+
+/**
+ * Perform the OP_2DUP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.dup2 = function dup2() {
+  var v1, v2;
+
+  if (this.length < 2)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2DUP);
+
+  v1 = this.top(-2);
+  v2 = this.top(-1);
+
+  this.push(v1);
+  this.push(v2);
+};
+
+/**
+ * Perform the OP_3DUP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.dup3 = function dup3() {
+  var v1, v2, v3;
+
+  if (this.length < 3)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_3DUP);
+
+  v1 = this.top(-3);
+  v2 = this.top(-2);
+  v3 = this.top(-1);
+
+  this.push(v1);
+  this.push(v2);
+  this.push(v3);
+};
+
+/**
+ * Perform the OP_2OVER operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.over2 = function over2() {
+  var v1, v2;
+
+  if (this.length < 4)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2OVER);
+
+  v1 = this.top(-4);
+  v2 = this.top(-3);
+
+  this.push(v1);
+  this.push(v2);
+};
+
+/**
+ * Perform the OP_2ROT operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.rot2 = function rot2() {
+  var v1, v2;
+
+  if (this.length < 6)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2ROT);
+
+  v1 = this.top(-6);
+  v2 = this.top(-5);
+
+  this.splice(this.length - 6, 2);
+  this.push(v1);
+  this.push(v2);
+};
+
+/**
+ * Perform the OP_2SWAP operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.swap2 = function swap2() {
+  if (this.length < 4)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_2SWAP);
+
+  this._swap(-4, -2);
+  this._swap(-3, -1);
+};
+
+/**
+ * Perform the OP_SIZE operation.
+ * @throws {ScriptError}
+ */
+
+Stack.prototype.size = function size() {
+  if (this.length < 1)
+    throw new ScriptError('INVALID_STACK_OPERATION', opcodes.OP_SIZE);
+
+  this.push(bcoin.script.array(this.top(-1).length));
+};
+
+/**
+ * Test an object to see if it is a Stack.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+Stack.isStack = function isStack(obj) {
+  return obj && Array.isArray(obj.items) && typeof obj.swap2 === 'function';
+};
+
+/*
+ * Expose
+ */
+
+module.exports = Stack;
diff --git a/lib/bcoin/script/witness.js b/lib/bcoin/script/witness.js
new file mode 100644
index 00000000..69716e4c
--- /dev/null
+++ b/lib/bcoin/script/witness.js
@@ -0,0 +1,613 @@
+/*!
+ * script.js - script interpreter for bcoin
+ * Copyright (c) 2014-2015, Fedor Indutny (MIT License)
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var bn = require('bn.js');
+var constants = bcoin.constants;
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var opcodes = constants.opcodes;
+var STACK_FALSE = new Buffer([]);
+var STACK_NEGATE = new Buffer([0x81]);
+var scriptTypes = constants.scriptTypes;
+var Script = require('./script');
+var Opcode = require('./opcode');
+
+/**
+ * Refers to the witness field of segregated witness transactions.
+ * @exports Witness
+ * @constructor
+ * @param {Buffer[]|NakedWitness} items - Array of
+ * stack items.
+ * @property {Buffer[]} items
+ * @property {Script?} redeem
+ * @property {Number} length
+ */
+
+function Witness(options) {
+  if (!(this instanceof Witness))
+    return new Witness(options);
+
+  this.items = [];
+
+  if (options)
+    this.fromOptions(options);
+}
+
+Witness.prototype.__defineGetter__('length', function() {
+  return this.items.length;
+});
+
+Witness.prototype.__defineSetter__('length', function(length) {
+  return this.items.length = length;
+});
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+Witness.prototype.fromOptions = function fromOptions(options) {
+  var items;
+
+  assert(options, 'Witness data is required.');
+
+  items = options.items;
+
+  if (!items)
+    items = options;
+
+  if (items)
+    this.fromArray(items);
+
+  return this;
+};
+
+/**
+ * Instantiate witness from options.
+ * @param {Object} options
+ * @returns {Witness}
+ */
+
+Witness.fromOptions = function fromOptions(options) {
+  return new Witness().fromOptions(options);
+};
+
+/**
+ * Convert witness to an array of buffers.
+ * @returns {Buffer[]}
+ */
+
+Witness.prototype.toArray = function toArray() {
+  return this.items.slice();
+};
+
+/**
+ * Inject properties from an array of buffers.
+ * @private
+ * @param {Buffer[]} items
+ */
+
+Witness.prototype.fromArray = function fromArray(items) {
+  assert(Array.isArray(items));
+  this.items = items;
+  return this;
+};
+
+/**
+ * Insantiate witness from an array of buffers.
+ * @param {Buffer[]} items
+ * @returns {Witness}
+ */
+
+Witness.fromArray = function fromArray(items) {
+  return new Witness().fromArray(items);
+};
+
+/**
+ * Inspect a Witness object.
+ * @returns {String} Human-readable script.
+ */
+
+Witness.prototype.inspect = function inspect() {
+  return '<Witness: ' + this.toString() + '>';
+};
+
+/**
+ * Convert a Witness object to a String.
+ * @returns {String} Human-readable script.
+ */
+
+Witness.prototype.toString = function toString() {
+  return Witness.format(this.items);
+};
+
+/**
+ * Format the witness object as bitcoind asm.
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable script.
+ */
+
+Witness.prototype.toASM = function toASM(decode) {
+  return Script.formatASM(Script.parseArray(this.items), decode);
+};
+
+/**
+ * Clone the witness object. Note that the raw
+ * encoded witness data will be lost. This is
+ * because the function assumes you are going
+ * to be altering the stack items by hand.
+ * @returns {Witness} A clone of the current witness object.
+ */
+
+Witness.prototype.clone = function clone() {
+  return new Witness(this.items.slice());
+};
+
+/**
+ * Convert the Witness to a Stack object.
+ * This is usually done before executing
+ * a witness program.
+ * @returns {Stack}
+ */
+
+Witness.prototype.toStack = function toStack() {
+  return new bcoin.stack(this.items.slice());
+};
+
+/**
+ * "Guess" the type of the witness.
+ * This method is not 100% reliable.
+ * @returns {ScriptType}
+ */
+
+Witness.prototype.getInputType = function getInputType() {
+  if (this.isPubkeyhashInput())
+    return scriptTypes.WITNESSPUBKEYHASH;
+
+  if (this.isScripthashInput())
+    return scriptTypes.WITNESSSCRIPTHASH;
+
+  return scriptTypes.NONSTANDARD;
+};
+
+/**
+ * "Guess" the address of the witness.
+ * This method is not 100% reliable.
+ * @returns {Address|null}
+ */
+
+Witness.prototype.getInputAddress = function getInputAddress() {
+  return bcoin.address.fromWitness(this);
+};
+
+/**
+ * "Test" whether the witness is a pubkey input.
+ * Always returns false.
+ * @returns {Boolean}
+ */
+
+Witness.prototype.isPubkeyInput = function isPubkeyInput() {
+  return false;
+};
+
+/**
+ * "Guess" whether the witness is a pubkeyhash input.
+ * This method is not 100% reliable.
+ * @returns {Boolean}
+ */
+
+Witness.prototype.isPubkeyhashInput = function isPubkeyhashInput() {
+  return this.items.length === 2
+    && Script.isSignatureEncoding(this.items[0])
+    && Script.isKeyEncoding(this.items[1]);
+};
+
+/**
+ * "Test" whether the witness is a multisig input.
+ * Always returns false.
+ * @returns {Boolean}
+ */
+
+Witness.prototype.isMultisigInput = function isMultisigInput() {
+  return false;
+};
+
+/**
+ * "Guess" whether the witness is a scripthash input.
+ * This method is not 100% reliable.
+ * @returns {Boolean}
+ */
+
+Witness.prototype.isScripthashInput = function isScripthashInput() {
+  return this.items.length > 0 && !this.isPubkeyhashInput();
+};
+
+/**
+ * "Guess" whether the witness is an unknown/non-standard type.
+ * This method is not 100% reliable.
+ * @returns {Boolean}
+ */
+
+Witness.prototype.isUnknownInput = function isUnknownInput() {
+  return this.getInputType() === scriptTypes.NONSTANDARD;
+};
+
+/**
+ * Test the witness against a bloom filter.
+ * @param {Bloom} filter
+ * @returns {Boolean}
+ */
+
+Witness.prototype.test = function test(filter) {
+  var i, chunk;
+
+  for (i = 0; i < this.items.length; i++) {
+    chunk = this.items[i];
+
+    if (chunk.length === 0)
+      continue;
+
+    if (filter.test(chunk))
+      return true;
+  }
+
+  return false;
+};
+
+/**
+ * Grab and deserialize the redeem script from the witness.
+ * @returns {Script} Redeem script.
+ */
+
+Witness.prototype.getRedeem = function getRedeem() {
+  var redeem = this.items[this.items.length - 1];
+
+  if (!redeem)
+    return;
+
+  return new Script(redeem);
+};
+
+/**
+ * Does nothing currently.
+ */
+
+Witness.prototype.compile = function compile() {
+  // NOP
+};
+
+/**
+ * Find a data element in a witness.
+ * @param {Buffer} data - Data element to match against.
+ * @returns {Number} Index (`-1` if not present).
+ */
+
+Witness.prototype.indexOf = function indexOf(data) {
+  return utils.indexOf(this.items, data);
+};
+
+/**
+ * Encode the witness to a Buffer.
+ * @param {String} enc - Encoding, either `'hex'` or `null`.
+ * @returns {Buffer|String} Serialized script.
+ */
+
+Witness.prototype.toRaw = function toRaw(writer) {
+  var p = bcoin.writer(writer);
+  var i;
+
+  p.writeVarint(this.items.length);
+
+  for (i = 0; i < this.items.length; i++)
+    p.writeVarBytes(this.items[i]);
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Convert witness to a hex string.
+ * @returns {String}
+ */
+
+Witness.prototype.toJSON = function toJSON() {
+  return this.toRaw().toString('hex');
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {String} json
+ */
+
+Witness.prototype.fromJSON = function fromJSON(json) {
+  assert(typeof json === 'string');
+  return this.fromRaw(new Buffer(json, 'hex'));
+};
+
+/**
+ * Insantiate witness from a hex string.
+ * @param {String} json
+ * @returns {Witness}
+ */
+
+Witness.fromJSON = function fromJSON(json) {
+  return new Witness().fromJSON(json);
+};
+
+/**
+ * Unshift an item onto the witness vector.
+ * @param {Number|String|Buffer|BN} data
+ * @returns {Number}
+ */
+
+Witness.prototype.unshift = function unshift(data) {
+  return this.items.unshift(Witness.encodeItem(data));
+};
+
+/**
+ * Push an item onto the witness vector.
+ * @param {Number|String|Buffer|BN} data
+ * @returns {Number}
+ */
+
+Witness.prototype.push = function push(data) {
+  return this.items.push(Witness.encodeItem(data));
+};
+
+/**
+ * Shift an item off the witness vector.
+ * @returns {Buffer}
+ */
+
+Witness.prototype.shift = function shift() {
+  return this.items.shift();
+};
+
+/**
+ * Shift an item off the witness vector.
+ * @returns {Buffer}
+ */
+
+Witness.prototype.pop = function push(data) {
+  return this.items.pop();
+};
+
+/**
+ * Remove an item from the witness vector.
+ * @param {Number} index
+ * @returns {Buffer}
+ */
+
+Witness.prototype.remove = function remove(i) {
+  return this.items.splice(i, 1)[0];
+};
+
+/**
+ * Insert an item into the witness vector.
+ * @param {Number} index
+ * @param {Number|String|Buffer|BN} data
+ */
+
+Witness.prototype.insert = function insert(i, data) {
+  assert(i <= this.items.length, 'Index out of bounds.');
+  this.items.splice(i, 0, Witness.encodeItem(data))[0];
+};
+
+/**
+ * Get an item from the witness vector.
+ * @param {Number} index
+ * @returns {Buffer}
+ */
+
+Witness.prototype.get = function get(i) {
+  return this.items[i];
+};
+
+/**
+ * Get a small int (0-16) from the witness vector.
+ * @param {Number} index
+ * @returns {Number} `-1` on non-existent.
+ */
+
+Witness.prototype.getSmall = function getSmall(i) {
+  var item = this.items[i];
+  if (!item || item.length > 1)
+    return -1;
+  if (item.length === 0)
+    return 0;
+  if (!(item[0] >= 1 && item[1] <= 16))
+    return -1;
+  return item[0];
+};
+
+/**
+ * Get a number from the witness vector.
+ * @param {Number} index
+ * @returns {BN}
+ */
+
+Witness.prototype.getNumber = function getNumber(i) {
+  var item = this.items[i];
+  if (!item || item.length > 5)
+    return;
+  return Script.num(item, constants.flags.VERIFY_NONE, 5);
+};
+
+/**
+ * Get a string from the witness vector.
+ * @param {Number} index
+ * @returns {String}
+ */
+
+Witness.prototype.getString = function getString(i) {
+  var item = this.items[i];
+  if (!item)
+    return;
+  return item.toString('utf8');
+};
+
+/**
+ * Clear the witness items.
+ */
+
+Witness.prototype.clear = function clear() {
+  this.items.length = 0;
+};
+
+/**
+ * Set an item in the witness vector.
+ * @param {Number} index
+ * @param {Number|String|Buffer|BN} data
+ */
+
+Witness.prototype.set = function set(i, data) {
+  assert(i <= this.items.length, 'Index out of bounds.');
+  this.items[i] = Witness.encodeItem(data);
+};
+
+/**
+ * Encode a witness item.
+ * @param {Number|String|Buffer|BN} data
+ * @returns {Buffer}
+ */
+
+Witness.encodeItem = function encodeItem(data) {
+  if (data instanceof Opcode)
+    data = data.data || data.value;
+
+  if (typeof data === 'number') {
+    if (data === opcodes.OP_1NEGATE)
+      return STACK_NEGATE;
+
+    if (data === opcodes.OP_0)
+      return STACK_FALSE;
+
+    if (data >= opcodes.OP_1 && data <= opcodes.OP_16)
+      return new Buffer([data - 0x50]);
+
+    throw new Error('Non-push opcode in witness.');
+  }
+
+  if (bn.isBN(data))
+    return Script.array(data);
+
+  if (typeof data === 'string')
+    return new Buffer(data, 'utf8');
+
+  return data;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} data
+ */
+
+Witness.prototype.fromRaw = function fromRaw(data) {
+  var p = bcoin.reader(data);
+  var chunkCount = p.readVarint();
+  var i;
+
+  for (i = 0; i < chunkCount; i++)
+    this.items.push(p.readVarBytes());
+
+  return this;
+};
+
+/**
+ * Create a Witness from a serialized buffer.
+ * @param {Buffer|String} data - Serialized witness.
+ * @param {String?} enc - Either `"hex"` or `null`.
+ * @returns {Witness}
+ */
+
+Witness.fromRaw = function fromRaw(data, enc) {
+  if (typeof data === 'string')
+    data = new Buffer(data, enc);
+  return new Witness().fromRaw(data);
+};
+
+/**
+ * Inject items from string.
+ * @private
+ * @param {String|String[]} items
+ */
+
+Witness.prototype.fromString = function fromString(items) {
+  var i;
+
+  if (!Array.isArray(items)) {
+    assert(typeof items === 'string');
+
+    items = items.trim();
+
+    if (items.length === 0)
+      return this;
+
+    items = items.split(/\s+/);
+  }
+
+  for (i = 0; i < items.length; i++)
+    this.items.push(new Buffer(items[i], 'hex'));
+
+  return this;
+};
+
+/**
+ * Parse a test script/array
+ * string into a witness object. _Must_
+ * contain only stack items (no non-push
+ * opcodes).
+ * @param {String|String[]} items - Script string.
+ * @returns {Witness}
+ * @throws Parse error.
+ */
+
+Witness.fromString = function fromString(items) {
+  return new Witness().fromString(items);
+};
+
+/**
+ * Format script code into a human readable-string.
+ * @param {Array} code
+ * @returns {String} Human-readable string.
+ */
+
+Witness.format = function format(items) {
+  var out = [];
+  var i;
+
+  for (i = 0; i < items.length; i++)
+    out.push(items[i].toString('hex'));
+
+  return out.join(' ');
+};
+
+/**
+ * Test an object to see if it is a Witness.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+Witness.isWitness = function isWitness(obj) {
+  return obj
+    && Array.isArray(obj.items)
+    && typeof obj.toStack === 'function';
+};
+
+/*
+ * Expose
+ */
+
+module.exports = Witness;
diff --git a/lib/bcoin/wallet/account.js b/lib/bcoin/wallet/account.js
new file mode 100644
index 00000000..c8245197
--- /dev/null
+++ b/lib/bcoin/wallet/account.js
@@ -0,0 +1,851 @@
+/*!
+ * account.js - account object for bcoin
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var BufferReader = require('../utils/reader');
+var BufferWriter = require('../utils/writer');
+
+/**
+ * Represents a BIP44 Account belonging to a {@link Wallet}.
+ * Note that this object does not enforce locks. Any method
+ * that does a write is internal API only and will lead
+ * to race conditions if used elsewhere.
+ * @exports Account
+ * @constructor
+ * @param {Object} options
+ * @param {WalletDB} options.db
+ * @param {HDPublicKey} options.accountKey
+ * @param {Boolean?} options.witness - Whether to use witness programs.
+ * @param {Number} options.accountIndex - The BIP44 account index.
+ * @param {Number?} options.receiveDepth - The index of the _next_ receiving
+ * address.
+ * @param {Number?} options.changeDepth - The index of the _next_ change
+ * address.
+ * @param {String?} options.type - Type of wallet (pubkeyhash, multisig)
+ * (default=pubkeyhash).
+ * @param {Number?} options.m - `m` value for multisig.
+ * @param {Number?} options.n - `n` value for multisig.
+ * @param {String?} options.wid - Wallet ID
+ * @param {String?} options.name - Account name
+ */
+
+function Account(db, options) {
+  if (!(this instanceof Account))
+    return new Account(db, options);
+
+  assert(db, 'Database is required.');
+
+  this.db = db;
+  this.network = db.network;
+  this.lookahead = Account.MAX_LOOKAHEAD;
+
+  this.receiveAddress = null;
+  this.changeAddress = null;
+
+  this.wid = 0;
+  this.id = null;
+  this.name = null;
+  this.witness = this.db.options.witness;
+  this.accountKey = null;
+  this.accountIndex = 0;
+  this.receiveDepth = 0;
+  this.changeDepth = 0;
+  this.type = Account.types.PUBKEYHASH;
+  this.m = 1;
+  this.n = 1;
+  this.keys = [];
+  this.initialized = false;
+
+  if (options)
+    this.fromOptions(options);
+}
+
+/**
+ * Account types.
+ * @enum {Number}
+ * @default
+ */
+
+Account.types = {
+  PUBKEYHASH: 0,
+  MULTISIG: 1
+};
+
+/**
+ * Account types by value.
+ * @const {RevMap}
+ */
+
+Account.typesByVal = {
+  0: 'pubkeyhash',
+  1: 'multisig'
+};
+
+/**
+ * Inject properties from options object.
+ * @private
+ * @param {Object} options
+ */
+
+Account.prototype.fromOptions = function fromOptions(options) {
+  var i;
+
+  assert(options, 'Options are required.');
+  assert(utils.isNumber(options.wid));
+  assert(utils.isName(options.id), 'Bad Wallet ID.');
+  assert(bcoin.hd.isHD(options.accountKey), 'Account key is required.');
+  assert(utils.isNumber(options.accountIndex), 'Account index is required.');
+
+  this.wid = options.wid;
+  this.id = options.id;
+
+  if (options.name != null) {
+    assert(utils.isName(options.name), 'Bad account name.');
+    this.name = options.name;
+  }
+
+  if (options.witness != null) {
+    assert(typeof options.witness === 'boolean');
+    this.witness = options.witness;
+  }
+
+  this.accountKey = options.accountKey;
+
+  if (options.accountIndex != null) {
+    assert(utils.isNumber(options.accountIndex));
+    this.accountIndex = options.accountIndex;
+  }
+
+  if (options.receiveDepth != null) {
+    assert(utils.isNumber(options.receiveDepth));
+    this.receiveDepth = options.receiveDepth;
+  }
+
+  if (options.changeDepth != null) {
+    assert(utils.isNumber(options.changeDepth));
+    this.changeDepth = options.changeDepth;
+  }
+
+  if (options.type != null) {
+    if (typeof options.type === 'string') {
+      this.type = Account.types[options.type.toUpperCase()];
+      assert(this.type != null);
+    } else {
+      assert(typeof options.type === 'number');
+      this.type = options.type;
+      assert(Account.typesByVal[this.type]);
+    }
+  }
+
+  if (options.m != null) {
+    assert(utils.isNumber(options.m));
+    this.m = options.m;
+  }
+
+  if (options.n != null) {
+    assert(utils.isNumber(options.n));
+    this.n = options.n;
+  }
+
+  if (options.initialized != null) {
+    assert(typeof options.initialized === 'boolean');
+    this.initialized = options.initialized;
+  }
+
+  if (this.n > 1)
+    this.type = Account.types.MULTISIG;
+
+  if (this.m < 1 || this.m > this.n)
+    throw new Error('m ranges between 1 and n');
+
+  if (!this.name)
+    this.name = this.accountIndex + '';
+
+  if (options.keys) {
+    assert(Array.isArray(options.keys));
+    for (i = 0; i < options.keys.length; i++)
+      this.pushKey(options.keys[i]);
+  }
+
+  return this;
+};
+
+/**
+ * Instantiate account from options.
+ * @param {WalletDB} db
+ * @param {Object} options
+ * @returns {Account}
+ */
+
+Account.fromOptions = function fromOptions(db, options) {
+  return new Account(db).fromOptions(options);
+};
+
+/*
+ * Default address lookahead.
+ * @const {Number}
+ */
+
+Account.MAX_LOOKAHEAD = 5;
+
+/**
+ * Attempt to intialize the account (generating
+ * the first addresses along with the lookahead
+ * addresses). Called automatically from the
+ * walletdb.
+ * @param {Function} callback
+ */
+
+Account.prototype.init = function init(callback) {
+  // Waiting for more keys.
+  if (this.keys.length !== this.n - 1) {
+    assert(!this.initialized);
+    this.save();
+    return callback();
+  }
+
+  assert(this.receiveDepth === 0);
+  assert(this.changeDepth === 0);
+
+  this.initialized = true;
+  this.setDepth(1, 1, callback);
+};
+
+/**
+ * Open the account (done after retrieval).
+ * @param {Function} callback
+ */
+
+Account.prototype.open = function open(callback) {
+  if (!this.initialized)
+    return callback();
+
+  this.receiveAddress = this.deriveReceive(this.receiveDepth - 1);
+  this.changeAddress = this.deriveChange(this.changeDepth - 1);
+
+  callback();
+};
+
+/**
+ * Add a public account key to the account (multisig).
+ * Does not update the database.
+ * @param {HDPublicKey} key - Account (bip44)
+ * key (can be in base58 form).
+ * @throws Error on non-hdkey/non-accountkey.
+ */
+
+Account.prototype.pushKey = function pushKey(key) {
+  var index;
+
+  if (bcoin.hd.isExtended(key))
+    key = bcoin.hd.fromBase58(key);
+
+  if (!bcoin.hd.isPublic(key))
+    throw new Error('Must add HD keys to wallet.');
+
+  if (!key.isAccount44())
+    throw new Error('Must add HD account keys to BIP44 wallet.');
+
+  if (key.equal(this.accountKey))
+    throw new Error('Cannot add own key.');
+
+  index = utils.binaryInsert(this.keys, key, cmp, true);
+
+  if (index === -1)
+    return false;
+
+  if (this.keys.length > this.n - 1) {
+    utils.binaryRemove(this.keys, key, cmp);
+    throw new Error('Cannot add more keys.');
+  }
+
+  return true;
+};
+
+/**
+ * Remove a public account key to the account (multisig).
+ * Does not update the database.
+ * @param {HDPublicKey} key - Account (bip44)
+ * key (can be in base58 form).
+ * @throws Error on non-hdkey/non-accountkey.
+ */
+
+Account.prototype.spliceKey = function spliceKey(key) {
+  if (bcoin.hd.isExtended(key))
+    key = bcoin.hd.fromBase58(key);
+
+  if (!bcoin.hd.isHDPublicKey(key))
+    throw new Error('Must add HD keys to wallet.');
+
+  if (!key.isAccount44())
+    throw new Error('Must add HD account keys to BIP44 wallet.');
+
+  if (key.equal(this.accountKey))
+    throw new Error('Cannot remove own key.');
+
+  if (this.keys.length === this.n - 1)
+    throw new Error('Cannot remove key.');
+
+  return utils.binaryRemove(this.keys, key, cmp);
+};
+
+/**
+ * Add a public account key to the account (multisig).
+ * Saves the key in the wallet database.
+ * @param {HDPublicKey} key
+ * @param {Function} callback
+ */
+
+Account.prototype.addKey = function addKey(key, callback) {
+  var self = this;
+  var result = false;
+
+  try {
+    result = this.pushKey(key);
+  } catch (e) {
+    return callback(e);
+  }
+
+  this._checkKeys(function(err, exists) {
+    if (err)
+      return callback(err);
+
+    if (exists) {
+      self.spliceKey(key);
+      return callback(new Error('Cannot add a key from another account.'));
+    }
+
+    // Try to initialize again.
+    self.init(function(err) {
+      if (err)
+        return callback(err);
+
+      callback(null, result);
+    });
+  });
+};
+
+/**
+ * Ensure accounts are not sharing keys.
+ * @private
+ * @param {Function} callback
+ */
+
+Account.prototype._checkKeys = function _checkKeys(callback) {
+  var self = this;
+  var ring, hash;
+
+  if (this.initialized || this.type !== Account.types.MULTISIG)
+    return callback(null, false);
+
+  if (this.keys.length !== this.n - 1)
+    return callback(null, false);
+
+  ring = this.deriveReceive(0);
+  hash = ring.getScriptHash('hex');
+
+  this.db.getAddressPaths(hash, function(err, paths) {
+    if (err)
+      return callback(err);
+
+    if (!paths)
+      return callback(null, false);
+
+    callback(null, paths[self.wid] != null);
+  });
+};
+
+/**
+ * Remove a public account key from the account (multisig).
+ * Remove the key from the wallet database.
+ * @param {HDPublicKey} key
+ * @param {Function} callback
+ */
+
+Account.prototype.removeKey = function removeKey(key, callback) {
+  var result = false;
+
+  try {
+    result = this.spliceKey(key);
+  } catch (e) {
+    return callback(e);
+  }
+
+  this.save();
+
+  callback(null, result);
+};
+
+/**
+ * Create a new receiving address (increments receiveDepth).
+ * @returns {KeyRing}
+ */
+
+Account.prototype.createReceive = function createReceive(callback) {
+  return this.createAddress(false, callback);
+};
+
+/**
+ * Create a new change address (increments receiveDepth).
+ * @returns {KeyRing}
+ */
+
+Account.prototype.createChange = function createChange(callback) {
+  return this.createAddress(true, callback);
+};
+
+/**
+ * Create a new address (increments depth).
+ * @param {Boolean} change
+ * @param {Function} callback - Returns [Error, {@link KeyRing}].
+ */
+
+Account.prototype.createAddress = function createAddress(change, callback) {
+  var self = this;
+  var ring, lookahead;
+
+  if (typeof change === 'function') {
+    callback = change;
+    change = false;
+  }
+
+  if (change) {
+    ring = this.deriveChange(this.changeDepth);
+    lookahead = this.deriveChange(this.changeDepth + this.lookahead);
+    this.changeDepth++;
+    this.changeAddress = ring;
+  } else {
+    ring = this.deriveReceive(this.receiveDepth);
+    lookahead = this.deriveReceive(this.receiveDepth + this.lookahead);
+    this.receiveDepth++;
+    this.receiveAddress = ring;
+  }
+
+  this.saveAddress([ring, lookahead], function(err) {
+    if (err)
+      return callback(err);
+
+    self.save();
+
+    callback(null, ring);
+  });
+};
+
+/**
+ * Derive a receiving address at `index`. Do not increment depth.
+ * @param {Number} index
+ * @returns {KeyRing}
+ */
+
+Account.prototype.deriveReceive = function deriveReceive(index, master) {
+  return this.deriveAddress(false, index, master);
+};
+
+/**
+ * Derive a change address at `index`. Do not increment depth.
+ * @param {Number} index
+ * @returns {KeyRing}
+ */
+
+Account.prototype.deriveChange = function deriveChange(index, master) {
+  return this.deriveAddress(true, index, master);
+};
+
+/**
+ * Derive an address from `path` object.
+ * @param {Path} path
+ * @param {MasterKey} master
+ * @returns {KeyRing}
+ */
+
+Account.prototype.derivePath = function derivePath(path, master) {
+  var ring, script, raw;
+
+  // Imported key.
+  if (path.index === -1) {
+    assert(path.imported);
+    assert(this.type === Account.types.PUBKEYHASH);
+
+    raw = path.imported;
+
+    if (path.encrypted)
+      raw = master.decipher(raw, path.hash);
+
+    if (!raw)
+      return;
+
+    ring = bcoin.keyring.fromRaw(raw, this.network);
+    ring.path = path;
+
+    return ring;
+  }
+
+  // Custom redeem script.
+  if (path.script)
+    script = new bcoin.script(path.script);
+
+  ring = this.deriveAddress(path.change, path.index, master, script);
+
+  return ring;
+};
+
+/**
+ * Derive an address at `index`. Do not increment depth.
+ * @param {Boolean} change - Whether the address on the change branch.
+ * @param {Number} index
+ * @returns {KeyRing}
+ */
+
+Account.prototype.deriveAddress = function deriveAddress(change, index, master, script) {
+  var keys = [];
+  var i, key, shared, ring;
+
+  change = +change;
+
+  if (master && master.key) {
+    key = master.key.deriveAccount44(this.accountIndex);
+    key = key.derive(change).derive(index);
+  } else {
+    key = this.accountKey.derive(change).derive(index);
+  }
+
+  ring = bcoin.keyring.fromPublic(key.publicKey, this.network);
+  ring.witness = this.witness;
+
+  if (script) {
+    // Custom redeem script.
+    assert(this.type === Account.types.PUBKEYHASH);
+    ring.script = script;
+  } else {
+    switch (this.type) {
+      case Account.types.PUBKEYHASH:
+        break;
+      case Account.types.MULTISIG:
+        keys.push(key.publicKey);
+
+        for (i = 0; i < this.keys.length; i++) {
+          shared = this.keys[i];
+          shared = shared.derive(change).derive(index);
+          keys.push(shared.publicKey);
+        }
+
+        ring.script = bcoin.script.fromMultisig(this.m, this.n, keys);
+
+        break;
+    }
+  }
+
+  if (key.privateKey)
+    ring.privateKey = key.privateKey;
+
+  ring.path = bcoin.path.fromAccount(this, ring, change, index);
+
+  return ring;
+};
+
+/**
+ * Save the account to the database. Necessary
+ * when address depth and keys change.
+ * @param {Function} callback
+ */
+
+Account.prototype.save = function save() {
+  return this.db.saveAccount(this);
+};
+
+/**
+ * Save addresses to path map.
+ * @param {KeyRing[]} rings
+ * @param {Function} callback
+ */
+
+Account.prototype.saveAddress = function saveAddress(rings, callback) {
+  return this.db.saveAddress(this.wid, rings, callback);
+};
+
+/**
+ * Set change and receiving depth (depth is the index of the _next_ address).
+ * Allocate all addresses up to depth. Note that this also allocates
+ * new lookahead addresses.
+ * @param {Number} depth
+ * @param {Function} callback - Returns [Error, {@link KeyRing}, {@link KeyRing}].
+ */
+
+Account.prototype.setDepth = function setDepth(receiveDepth, changeDepth, callback) {
+  var self = this;
+  var rings = [];
+  var i, receive, change;
+
+  if (receiveDepth > this.receiveDepth) {
+    for (i = this.receiveDepth; i < receiveDepth; i++) {
+      receive = this.deriveReceive(i);
+      rings.push(receive);
+    }
+
+    for (i = receiveDepth; i < receiveDepth + this.lookahead; i++)
+      rings.push(this.deriveReceive(i));
+
+    this.receiveAddress = receive;
+    this.receiveDepth = receiveDepth;
+  }
+
+  if (changeDepth > this.changeDepth) {
+    for (i = this.changeDepth; i < changeDepth; i++) {
+      change = this.deriveChange(i);
+      rings.push(change);
+    }
+
+    for (i = changeDepth; i < changeDepth + this.lookahead; i++)
+      rings.push(this.deriveChange(i));
+
+    this.changeAddress = change;
+    this.changeDepth = changeDepth;
+  }
+
+  if (rings.length === 0)
+    return callback();
+
+  this.saveAddress(rings, function(err) {
+    if (err)
+      return callback(err);
+
+    self.save();
+
+    callback(null, receive, change);
+  });
+};
+
+/**
+ * Convert the account to a more inspection-friendly object.
+ * @returns {Object}
+ */
+
+Account.prototype.inspect = function inspect() {
+  return {
+    wid: this.wid,
+    name: this.name,
+    network: this.network,
+    initialized: this.initialized,
+    type: Account.typesByVal[this.type].toLowerCase(),
+    m: this.m,
+    n: this.n,
+    address: this.initialized
+      ? this.receiveAddress.getAddress()
+      : null,
+    programAddress: this.initialized
+      ? this.receiveAddress.getProgramAddress()
+      : null,
+    witness: this.witness,
+    accountIndex: this.accountIndex,
+    receiveDepth: this.receiveDepth,
+    changeDepth: this.changeDepth,
+    accountKey: this.accountKey.xpubkey,
+    keys: this.keys.map(function(key) {
+      return key.xpubkey;
+    })
+  };
+};
+
+/**
+ * Convert the account to an object suitable for
+ * serialization.
+ * @returns {Object}
+ */
+
+Account.prototype.toJSON = function toJSON() {
+  return {
+    network: this.network.type,
+    wid: this.wid,
+    name: this.name,
+    initialized: this.initialized,
+    type: Account.typesByVal[this.type].toLowerCase(),
+    m: this.m,
+    n: this.n,
+    witness: this.witness,
+    accountIndex: this.accountIndex,
+    receiveDepth: this.receiveDepth,
+    changeDepth: this.changeDepth,
+    receiveAddress: this.receiveAddress
+      ? this.receiveAddress.getAddress('base58')
+      : null,
+    programAddress: this.receiveAddress
+      ? this.receiveAddress.getProgramAddress('base58')
+      : null,
+    changeAddress: this.changeAddress
+      ? this.changeAddress.getAddress('base58')
+      : null,
+    accountKey: this.accountKey.xpubkey,
+    keys: this.keys.map(function(key) {
+      return key.xpubkey;
+    })
+  };
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {Object} json
+ */
+
+Account.prototype.fromJSON = function fromJSON(json) {
+  var i, key;
+
+  assert.equal(json.network, this.network.type);
+  assert(utils.isNumber(json.wid));
+  assert(utils.isName(json.id), 'Bad wallet ID.');
+  assert(utils.isName(json.name), 'Bad account name.');
+  assert(typeof json.initialized === 'boolean');
+  assert(typeof json.type === 'string');
+  assert(utils.isNumber(json.m));
+  assert(utils.isNumber(json.n));
+  assert(typeof json.witness === 'boolean');
+  assert(utils.isNumber(json.accountIndex));
+  assert(utils.isNumber(json.receiveDepth));
+  assert(utils.isNumber(json.changeDepth));
+  assert(Array.isArray(json.keys));
+
+  this.wid = json.wid;
+  this.name = json.name;
+  this.initialized = json.initialized;
+  this.type = Account.types[json.type.toUpperCase()];
+  this.m = json.m;
+  this.n = json.n;
+  this.witness = json.witness;
+  this.accountIndex = json.accountIndex;
+  this.receiveDepth = json.receiveDepth;
+  this.changeDepth = json.changeDepth;
+  this.accountKey = bcoin.hd.fromBase58(json.accountKey);
+
+  assert(this.type != null);
+
+  for (i = 0; i < json.keys.length; i++) {
+    key = bcoin.hd.fromBase58(json.keys[i]);
+    this.pushKey(key);
+  }
+
+  return this;
+};
+
+/**
+ * Serialize the account.
+ * @returns {Buffer}
+ */
+
+Account.prototype.toRaw = function toRaw(writer) {
+  var p = new BufferWriter(writer);
+  var i, key;
+
+  p.writeU32(this.network.magic);
+  p.writeVarString(this.name, 'utf8');
+  p.writeU8(this.initialized ? 1 : 0);
+  p.writeU8(this.type);
+  p.writeU8(this.m);
+  p.writeU8(this.n);
+  p.writeU8(this.witness ? 1 : 0);
+  p.writeU32(this.accountIndex);
+  p.writeU32(this.receiveDepth);
+  p.writeU32(this.changeDepth);
+  p.writeBytes(this.accountKey.toRaw());
+  p.writeU8(this.keys.length);
+
+  for (i = 0; i < this.keys.length; i++) {
+    key = this.keys[i];
+    p.writeBytes(key.toRaw());
+  }
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} data
+ * @returns {Object}
+ */
+
+Account.prototype.fromRaw = function fromRaw(data) {
+  var p = new BufferReader(data);
+  var i, count, key;
+
+  this.network = bcoin.network.fromMagic(p.readU32());
+  this.name = p.readVarString('utf8');
+  this.initialized = p.readU8() === 1;
+  this.type = p.readU8();
+  this.m = p.readU8();
+  this.n = p.readU8();
+  this.witness = p.readU8() === 1;
+  this.accountIndex = p.readU32();
+  this.receiveDepth = p.readU32();
+  this.changeDepth = p.readU32();
+  this.accountKey = bcoin.hd.fromRaw(p.readBytes(82));
+
+  assert(Account.typesByVal[this.type]);
+
+  count = p.readU8();
+
+  for (i = 0; i < count; i++) {
+    key = bcoin.hd.fromRaw(p.readBytes(82));
+    this.pushKey(key);
+  }
+
+  return this;
+};
+
+/**
+ * Instantiate a account from serialized data.
+ * @param {WalletDB} data
+ * @param {Buffer} data
+ * @returns {Account}
+ */
+
+Account.fromRaw = function fromRaw(db, data) {
+  return new Account(db).fromRaw(data);
+};
+
+/**
+ * Instantiate a Account from a
+ * jsonified account object.
+ * @param {WalletDB} db
+ * @param {Object} json - The jsonified account object.
+ * @returns {Account}
+ */
+
+Account.fromJSON = function fromJSON(db, json) {
+  return new Account(db).fromJSON(json);
+};
+
+/**
+ * Test an object to see if it is a Account.
+ * @param {Object} obj
+ * @returns {Boolean}
+ */
+
+Account.isAccount = function isAccount(obj) {
+  return obj
+    && typeof obj.receiveDepth === 'number'
+    && obj.deriveAddress === 'function';
+};
+
+/*
+ * Helpers
+ */
+
+function cmp(key1, key2) {
+  return key1.compare(key2);
+}
+
+/*
+ * Expose
+ */
+
+module.exports = Account;
diff --git a/lib/bcoin/wallet/path.js b/lib/bcoin/wallet/path.js
new file mode 100644
index 00000000..1228b027
--- /dev/null
+++ b/lib/bcoin/wallet/path.js
@@ -0,0 +1,285 @@
+/*!
+ * path.js - path object for wallets
+ * Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+var bcoin = require('../env');
+var utils = require('../utils/utils');
+var assert = utils.assert;
+var constants = bcoin.constants;
+var BufferReader = require('../utils/reader');
+var BufferWriter = require('../utils/writer');
+
+/**
+ * Path
+ * @constructor
+ * @private
+ * @property {WalletID} wid
+ * @property {String} name - Account name.
+ * @property {Number} account - Account index.
+ * @property {Number} change - Change index.
+ * @property {Number} index - Address index.
+ * @property {Address|null} address
+ */
+
+function Path() {
+  if (!(this instanceof Path))
+    return new Path();
+
+  this.wid = null;
+  this.name = null;
+  this.account = 0;
+  this.change = -1;
+  this.index = -1;
+
+  this.encrypted = false;
+  this.imported = null;
+  this.script = null;
+
+  // Currently unused.
+  this.type = bcoin.script.types.PUBKEYHASH;
+  this.version = -1;
+
+  // Passed in by caller.
+  this.id = null;
+  this.hash = null;
+}
+
+/**
+ * Clone the path object.
+ * @returns {Path}
+ */
+
+Path.prototype.clone = function clone() {
+  var path = new Path();
+
+  path.wid = this.wid;
+  path.name = this.name;
+  path.account = this.account;
+  path.change = this.change;
+  path.index = this.index;
+
+  path.encrypted = this.encrypted;
+  path.imported = this.imported;
+  path.script = this.script;
+
+  path.type = this.type;
+  path.version = this.version;
+
+  path.id = this.id;
+  path.hash = this.hash;
+
+  return path;
+};
+
+/**
+ * Inject properties from serialized data.
+ * @private
+ * @param {Buffer} data
+ */
+
+Path.prototype.fromRaw = function fromRaw(data) {
+  var p = new BufferReader(data);
+
+  this.wid = p.readU32();
+  this.name = p.readVarString('utf8');
+  this.account = p.readU32();
+
+  switch (p.readU8()) {
+    case 0:
+      this.change = p.readU32();
+      this.index = p.readU32();
+      if (p.readU8() === 1)
+        this.script = p.readVarBytes();
+      break;
+    case 1:
+      this.encrypted = p.readU8() === 1;
+      this.imported = p.readVarBytes();
+      this.change = -1;
+      this.index = -1;
+      break;
+    default:
+      assert(false);
+      break;
+  }
+
+  this.version = p.read8();
+  this.type = p.readU8();
+
+  return this;
+};
+
+/**
+ * Instantiate path from serialized data.
+ * @param {Buffer} data
+ * @returns {Path}
+ */
+
+Path.fromRaw = function fromRaw(data) {
+  return new Path().fromRaw(data);
+};
+
+/**
+ * Serialize path.
+ * @returns {Buffer}
+ */
+
+Path.prototype.toRaw = function toRaw(writer) {
+  var p = new BufferWriter(writer);
+
+  p.writeU32(this.wid);
+  p.writeVarString(this.name, 'utf8');
+  p.writeU32(this.account);
+
+  if (this.index !== -1) {
+    assert(!this.imported);
+    p.writeU8(0);
+    p.writeU32(this.change);
+    p.writeU32(this.index);
+    if (this.script) {
+      p.writeU8(1);
+      p.writeVarBytes(this.script);
+    } else {
+      p.writeU8(0);
+    }
+  } else {
+    assert(this.imported);
+    p.writeU8(1);
+    p.writeU8(this.encrypted ? 1 : 0);
+    p.writeVarBytes(this.imported);
+  }
+
+  p.write8(this.version);
+  p.writeU8(this.type);
+
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+/**
+ * Inject properties from account.
+ * @private
+ * @param {WalletID} wid
+ * @param {KeyRing} ring
+ */
+
+Path.prototype.fromAccount = function fromAccount(account, ring, change, index) {
+  this.wid = account.wid;
+  this.name = account.name;
+  this.account = account.accountIndex;
+
+  if (change != null)
+    this.change = change;
+
+  if (index != null)
+    this.index = index;
+
+  this.version = ring.witness ? 0 : -1;
+  this.type = ring.getType();
+
+  this.id = account.id;
+  this.hash = ring.getHash('hex');
+
+  return this;
+};
+
+/**
+ * Instantiate path from keyring.
+ * @param {WalletID} wid
+ * @param {KeyRing} ring
+ * @returns {Path}
+ */
+
+Path.fromAccount = function fromAccount(account, ring, change, index) {
+  return new Path().fromAccount(account, ring, change, index);
+};
+
+/**
+ * Convert path object to string derivation path.
+ * @returns {String}
+ */
+
+Path.prototype.toPath = function toPath() {
+  return 'm/' + this.account
+    + '\'/' + this.change
+    + '/' + this.index;
+};
+
+/**
+ * Convert path object to an address (currently unused).
+ * @returns {Address}
+ */
+
+Path.prototype.toAddress = function toAddress(network) {
+  return bcoin.address.fromHash(this.hash, this.type, this.version, network);
+};
+
+/**
+ * Convert path to a json-friendly object.
+ * @returns {Object}
+ */
+
+Path.prototype.toJSON = function toJSON() {
+  return {
+    name: this.name,
+    change: this.change === 1,
+    path: this.toPath()
+  };
+};
+
+/**
+ * Inject properties from json object.
+ * @private
+ * @param {Object} json
+ */
+
+Path.prototype.fromJSON = function fromJSON(json) {
+  var indexes = bcoin.hd.parsePath(json.path, constants.hd.MAX_INDEX);
+
+  assert(indexes.length === 3);
+  assert(indexes[0] >= constants.hd.HARDENED);
+  indexes[0] -= constants.hd.HARDENED;
+
+  this.wid = json.wid;
+  this.id = json.id;
+  this.name = json.name;
+  this.account = indexes[0];
+  this.change = indexes[1];
+  this.index = indexes[2];
+
+  return this;
+};
+
+/**
+ * Instantiate path from json object.
+ * @param {Object} json
+ * @returns {Path}
+ */
+
+Path.fromJSON = function fromJSON(json) {
+  return new Path().fromJSON(json);
+};
+
+/**
+ * Inspect the path.
+ * @returns {String}
+ */
+
+Path.prototype.inspect = function() {
+  return '<Path: ' + this.id
+    + '(' + this.wid + ')'
+    + '/' + this.name
+    + ': ' + this.toPath()
+    + '>';
+};
+
+/**
+ * Expose
+ */
+
+module.exports = Path;
diff --git a/lib/bcoin/wallet/txdb.js b/lib/bcoin/wallet/txdb.js
index 24c6d8d5..f5f71d43 100644
--- a/lib/bcoin/wallet/txdb.js
+++ b/lib/bcoin/wallet/txdb.js
@@ -2327,120 +2327,6 @@ TXDB.prototype.abandon = function abandon(hash, callback) {
   });
 };
 
-/**
- * Details
- */
-
-function Details(info) {
-  if (!(this instanceof Details))
-    return new Details(info);
-
-  this.db = info.db;
-  this.network = info.db.network;
-  this.wid = info.wid;
-  this.id = info.id;
-  this.hash = info.tx.hash('hex');
-  this.height = info.tx.height;
-  this.block = info.tx.block;
-  this.index = info.tx.index;
-  this.confirmations = info.tx.getConfirmations(this.db.height);
-  this.fee = info.tx.getFee();
-  this.ts = info.tx.ts;
-  this.ps = info.tx.ps;
-  this.tx = info.tx;
-  this.inputs = [];
-  this.outputs = [];
-
-  this.init(info.table);
-}
-
-Details.prototype.init = function init(table) {
-  this._insert(this.tx.inputs, this.inputs, table);
-  this._insert(this.tx.outputs, this.outputs, table);
-};
-
-Details.prototype._insert = function _insert(vector, target, table) {
-  var i, j, io, address, hash, paths, path, member;
-
-  for (i = 0; i < vector.length; i++) {
-    io = vector[i];
-    member = new DetailsMember();
-
-    if (io instanceof bcoin.input)
-      member.value = io.coin ? io.coin.value : 0;
-    else
-      member.value = io.value;
-
-    address = io.getAddress();
-
-    if (address) {
-      member.address = address;
-
-      hash = address.getHash('hex');
-      paths = table[hash];
-
-      for (j = 0; j < paths.length; j++) {
-        path = paths[j];
-        if (path.wid === this.wid) {
-          path.id = this.id;
-          member.path = path;
-          break;
-        }
-      }
-    }
-
-    target.push(member);
-  }
-};
-
-Details.prototype.toJSON = function toJSON() {
-  var self = this;
-  return {
-    wid: this.wid,
-    id: this.id,
-    hash: utils.revHex(this.hash),
-    height: this.height,
-    block: this.block ? utils.revHex(this.block) : null,
-    ts: this.ts,
-    ps: this.ps,
-    index: this.index,
-    fee: utils.btc(this.fee),
-    confirmations: this.confirmations,
-    inputs: this.inputs.map(function(input) {
-      return input.toJSON(self.network);
-    }),
-    outputs: this.outputs.map(function(output) {
-      return output.toJSON(self.network);
-    }),
-    tx: this.tx.toRaw().toString('hex')
-  };
-};
-
-/**
- * DetailsMember
- */
-
-function DetailsMember() {
-  if (!(this instanceof DetailsMember))
-    return new DetailsMember();
-
-  this.value = 0;
-  this.address = null;
-  this.path = null;
-}
-
-DetailsMember.prototype.toJSON = function toJSON(network) {
-  return {
-    value: utils.btc(this.value),
-    address: this.address
-      ? this.address.toBase58(network)
-      : null,
-    path: this.path
-      ? this.path.toJSON()
-      : null
-  };
-};
-
 /*
  * Balance
  */
@@ -2522,5 +2408,4 @@ function sortCoins(coins) {
  * Expose
  */
 
-TXDB.Details = Details;
 module.exports = TXDB;
diff --git a/lib/bcoin/wallet/wallet.js b/lib/bcoin/wallet/wallet.js
index a5d48b52..ff99c86d 100644
--- a/lib/bcoin/wallet/wallet.js
+++ b/lib/bcoin/wallet/wallet.js
@@ -15,6 +15,7 @@ var assert = utils.assert;
 var BufferReader = require('../utils/reader');
 var BufferWriter = require('../utils/writer');
 var TXDB = require('./txdb');
+var Path = require('./path');
 
 /**
  * BIP44 Wallet
@@ -834,7 +835,7 @@ Wallet.prototype.importKey = function importKey(account, ring, passphrase, callb
       if (!account)
         return callback(new Error('Account not found.'));
 
-      if (account.type !== Account.types.PUBKEYHASH)
+      if (account.type !== bcoin.account.types.PUBKEYHASH)
         return callback(new Error('Cannot import into non-pkh account.'));
 
       self.unlock(passphrase, null, function(err) {
@@ -842,7 +843,7 @@ Wallet.prototype.importKey = function importKey(account, ring, passphrase, callb
           return callback(err);
 
         raw = ring.toRaw();
-        path = bcoin.path.fromAccount(account, ring);
+        path = Path.fromAccount(account, ring);
 
         if (self.master.encrypted) {
           raw = self.master.encipher(raw, path.hash);
@@ -2112,830 +2113,6 @@ Wallet.isWallet = function isWallet(obj) {
     && obj.template === 'function';
 };
 
-/**
- * Represents a BIP44 Account belonging to a {@link Wallet}.
- * Note that this object does not enforce locks. Any method
- * that does a write is internal API only and will lead
- * to race conditions if used elsewhere.
- * @exports Account
- * @constructor
- * @param {Object} options
- * @param {WalletDB} options.db
- * @param {HDPublicKey} options.accountKey
- * @param {Boolean?} options.witness - Whether to use witness programs.
- * @param {Number} options.accountIndex - The BIP44 account index.
- * @param {Number?} options.receiveDepth - The index of the _next_ receiving
- * address.
- * @param {Number?} options.changeDepth - The index of the _next_ change
- * address.
- * @param {String?} options.type - Type of wallet (pubkeyhash, multisig)
- * (default=pubkeyhash).
- * @param {Number?} options.m - `m` value for multisig.
- * @param {Number?} options.n - `n` value for multisig.
- * @param {String?} options.wid - Wallet ID
- * @param {String?} options.name - Account name
- */
-
-function Account(db, options) {
-  if (!(this instanceof Account))
-    return new Account(db, options);
-
-  assert(db, 'Database is required.');
-
-  this.db = db;
-  this.network = db.network;
-  this.lookahead = Account.MAX_LOOKAHEAD;
-
-  this.receiveAddress = null;
-  this.changeAddress = null;
-
-  this.wid = 0;
-  this.id = null;
-  this.name = null;
-  this.witness = this.db.options.witness;
-  this.accountKey = null;
-  this.accountIndex = 0;
-  this.receiveDepth = 0;
-  this.changeDepth = 0;
-  this.type = Account.types.PUBKEYHASH;
-  this.m = 1;
-  this.n = 1;
-  this.keys = [];
-  this.initialized = false;
-
-  if (options)
-    this.fromOptions(options);
-}
-
-/**
- * Account types.
- * @enum {Number}
- * @default
- */
-
-Account.types = {
-  PUBKEYHASH: 0,
-  MULTISIG: 1
-};
-
-/**
- * Account types by value.
- * @const {RevMap}
- */
-
-Account.typesByVal = {
-  0: 'pubkeyhash',
-  1: 'multisig'
-};
-
-/**
- * Inject properties from options object.
- * @private
- * @param {Object} options
- */
-
-Account.prototype.fromOptions = function fromOptions(options) {
-  var i;
-
-  assert(options, 'Options are required.');
-  assert(utils.isNumber(options.wid));
-  assert(utils.isName(options.id), 'Bad Wallet ID.');
-  assert(bcoin.hd.isHD(options.accountKey), 'Account key is required.');
-  assert(utils.isNumber(options.accountIndex), 'Account index is required.');
-
-  this.wid = options.wid;
-  this.id = options.id;
-
-  if (options.name != null) {
-    assert(utils.isName(options.name), 'Bad account name.');
-    this.name = options.name;
-  }
-
-  if (options.witness != null) {
-    assert(typeof options.witness === 'boolean');
-    this.witness = options.witness;
-  }
-
-  this.accountKey = options.accountKey;
-
-  if (options.accountIndex != null) {
-    assert(utils.isNumber(options.accountIndex));
-    this.accountIndex = options.accountIndex;
-  }
-
-  if (options.receiveDepth != null) {
-    assert(utils.isNumber(options.receiveDepth));
-    this.receiveDepth = options.receiveDepth;
-  }
-
-  if (options.changeDepth != null) {
-    assert(utils.isNumber(options.changeDepth));
-    this.changeDepth = options.changeDepth;
-  }
-
-  if (options.type != null) {
-    if (typeof options.type === 'string') {
-      this.type = Account.types[options.type.toUpperCase()];
-      assert(this.type != null);
-    } else {
-      assert(typeof options.type === 'number');
-      this.type = options.type;
-      assert(Account.typesByVal[this.type]);
-    }
-  }
-
-  if (options.m != null) {
-    assert(utils.isNumber(options.m));
-    this.m = options.m;
-  }
-
-  if (options.n != null) {
-    assert(utils.isNumber(options.n));
-    this.n = options.n;
-  }
-
-  if (options.initialized != null) {
-    assert(typeof options.initialized === 'boolean');
-    this.initialized = options.initialized;
-  }
-
-  if (this.n > 1)
-    this.type = Account.types.MULTISIG;
-
-  if (this.m < 1 || this.m > this.n)
-    throw new Error('m ranges between 1 and n');
-
-  if (!this.name)
-    this.name = this.accountIndex + '';
-
-  if (options.keys) {
-    assert(Array.isArray(options.keys));
-    for (i = 0; i < options.keys.length; i++)
-      this.pushKey(options.keys[i]);
-  }
-
-  return this;
-};
-
-/**
- * Instantiate account from options.
- * @param {WalletDB} db
- * @param {Object} options
- * @returns {Account}
- */
-
-Account.fromOptions = function fromOptions(db, options) {
-  return new Account(db).fromOptions(options);
-};
-
-/*
- * Default address lookahead.
- * @const {Number}
- */
-
-Account.MAX_LOOKAHEAD = 5;
-
-/**
- * Attempt to intialize the account (generating
- * the first addresses along with the lookahead
- * addresses). Called automatically from the
- * walletdb.
- * @param {Function} callback
- */
-
-Account.prototype.init = function init(callback) {
-  // Waiting for more keys.
-  if (this.keys.length !== this.n - 1) {
-    assert(!this.initialized);
-    this.save();
-    return callback();
-  }
-
-  assert(this.receiveDepth === 0);
-  assert(this.changeDepth === 0);
-
-  this.initialized = true;
-  this.setDepth(1, 1, callback);
-};
-
-/**
- * Open the account (done after retrieval).
- * @param {Function} callback
- */
-
-Account.prototype.open = function open(callback) {
-  if (!this.initialized)
-    return callback();
-
-  this.receiveAddress = this.deriveReceive(this.receiveDepth - 1);
-  this.changeAddress = this.deriveChange(this.changeDepth - 1);
-
-  callback();
-};
-
-/**
- * Add a public account key to the account (multisig).
- * Does not update the database.
- * @param {HDPublicKey} key - Account (bip44)
- * key (can be in base58 form).
- * @throws Error on non-hdkey/non-accountkey.
- */
-
-Account.prototype.pushKey = function pushKey(key) {
-  var index;
-
-  if (bcoin.hd.isExtended(key))
-    key = bcoin.hd.fromBase58(key);
-
-  if (!bcoin.hd.isPublic(key))
-    throw new Error('Must add HD keys to wallet.');
-
-  if (!key.isAccount44())
-    throw new Error('Must add HD account keys to BIP44 wallet.');
-
-  if (key.equal(this.accountKey))
-    throw new Error('Cannot add own key.');
-
-  index = utils.binaryInsert(this.keys, key, cmp, true);
-
-  if (index === -1)
-    return false;
-
-  if (this.keys.length > this.n - 1) {
-    utils.binaryRemove(this.keys, key, cmp);
-    throw new Error('Cannot add more keys.');
-  }
-
-  return true;
-};
-
-/**
- * Remove a public account key to the account (multisig).
- * Does not update the database.
- * @param {HDPublicKey} key - Account (bip44)
- * key (can be in base58 form).
- * @throws Error on non-hdkey/non-accountkey.
- */
-
-Account.prototype.spliceKey = function spliceKey(key) {
-  if (bcoin.hd.isExtended(key))
-    key = bcoin.hd.fromBase58(key);
-
-  if (!bcoin.hd.isHDPublicKey(key))
-    throw new Error('Must add HD keys to wallet.');
-
-  if (!key.isAccount44())
-    throw new Error('Must add HD account keys to BIP44 wallet.');
-
-  if (key.equal(this.accountKey))
-    throw new Error('Cannot remove own key.');
-
-  if (this.keys.length === this.n - 1)
-    throw new Error('Cannot remove key.');
-
-  return utils.binaryRemove(this.keys, key, cmp);
-};
-
-/**
- * Add a public account key to the account (multisig).
- * Saves the key in the wallet database.
- * @param {HDPublicKey} key
- * @param {Function} callback
- */
-
-Account.prototype.addKey = function addKey(key, callback) {
-  var self = this;
-  var result = false;
-
-  try {
-    result = this.pushKey(key);
-  } catch (e) {
-    return callback(e);
-  }
-
-  this._checkKeys(function(err, exists) {
-    if (err)
-      return callback(err);
-
-    if (exists) {
-      self.spliceKey(key);
-      return callback(new Error('Cannot add a key from another account.'));
-    }
-
-    // Try to initialize again.
-    self.init(function(err) {
-      if (err)
-        return callback(err);
-
-      callback(null, result);
-    });
-  });
-};
-
-/**
- * Ensure accounts are not sharing keys.
- * @private
- * @param {Function} callback
- */
-
-Account.prototype._checkKeys = function _checkKeys(callback) {
-  var self = this;
-  var ring, hash;
-
-  if (this.initialized || this.type !== Account.types.MULTISIG)
-    return callback(null, false);
-
-  if (this.keys.length !== this.n - 1)
-    return callback(null, false);
-
-  ring = this.deriveReceive(0);
-  hash = ring.getScriptHash('hex');
-
-  this.db.getAddressPaths(hash, function(err, paths) {
-    if (err)
-      return callback(err);
-
-    if (!paths)
-      return callback(null, false);
-
-    callback(null, paths[self.wid] != null);
-  });
-};
-
-/**
- * Remove a public account key from the account (multisig).
- * Remove the key from the wallet database.
- * @param {HDPublicKey} key
- * @param {Function} callback
- */
-
-Account.prototype.removeKey = function removeKey(key, callback) {
-  var result = false;
-
-  try {
-    result = this.spliceKey(key);
-  } catch (e) {
-    return callback(e);
-  }
-
-  this.save();
-
-  callback(null, result);
-};
-
-/**
- * Create a new receiving address (increments receiveDepth).
- * @returns {KeyRing}
- */
-
-Account.prototype.createReceive = function createReceive(callback) {
-  return this.createAddress(false, callback);
-};
-
-/**
- * Create a new change address (increments receiveDepth).
- * @returns {KeyRing}
- */
-
-Account.prototype.createChange = function createChange(callback) {
-  return this.createAddress(true, callback);
-};
-
-/**
- * Create a new address (increments depth).
- * @param {Boolean} change
- * @param {Function} callback - Returns [Error, {@link KeyRing}].
- */
-
-Account.prototype.createAddress = function createAddress(change, callback) {
-  var self = this;
-  var ring, lookahead;
-
-  if (typeof change === 'function') {
-    callback = change;
-    change = false;
-  }
-
-  if (change) {
-    ring = this.deriveChange(this.changeDepth);
-    lookahead = this.deriveChange(this.changeDepth + this.lookahead);
-    this.changeDepth++;
-    this.changeAddress = ring;
-  } else {
-    ring = this.deriveReceive(this.receiveDepth);
-    lookahead = this.deriveReceive(this.receiveDepth + this.lookahead);
-    this.receiveDepth++;
-    this.receiveAddress = ring;
-  }
-
-  this.saveAddress([ring, lookahead], function(err) {
-    if (err)
-      return callback(err);
-
-    self.save();
-
-    callback(null, ring);
-  });
-};
-
-/**
- * Derive a receiving address at `index`. Do not increment depth.
- * @param {Number} index
- * @returns {KeyRing}
- */
-
-Account.prototype.deriveReceive = function deriveReceive(index, master) {
-  return this.deriveAddress(false, index, master);
-};
-
-/**
- * Derive a change address at `index`. Do not increment depth.
- * @param {Number} index
- * @returns {KeyRing}
- */
-
-Account.prototype.deriveChange = function deriveChange(index, master) {
-  return this.deriveAddress(true, index, master);
-};
-
-/**
- * Derive an address from `path` object.
- * @param {Path} path
- * @param {MasterKey} master
- * @returns {KeyRing}
- */
-
-Account.prototype.derivePath = function derivePath(path, master) {
-  var ring, script, raw;
-
-  // Imported key.
-  if (path.index === -1) {
-    assert(path.imported);
-    assert(this.type === Account.types.PUBKEYHASH);
-
-    raw = path.imported;
-
-    if (path.encrypted)
-      raw = master.decipher(raw, path.hash);
-
-    if (!raw)
-      return;
-
-    ring = bcoin.keyring.fromRaw(raw, this.network);
-    ring.path = path;
-
-    return ring;
-  }
-
-  // Custom redeem script.
-  if (path.script)
-    script = new bcoin.script(path.script);
-
-  ring = this.deriveAddress(path.change, path.index, master, script);
-
-  return ring;
-};
-
-/**
- * Derive an address at `index`. Do not increment depth.
- * @param {Boolean} change - Whether the address on the change branch.
- * @param {Number} index
- * @returns {KeyRing}
- */
-
-Account.prototype.deriveAddress = function deriveAddress(change, index, master, script) {
-  var keys = [];
-  var i, key, shared, ring;
-
-  change = +change;
-
-  if (master && master.key) {
-    key = master.key.deriveAccount44(this.accountIndex);
-    key = key.derive(change).derive(index);
-  } else {
-    key = this.accountKey.derive(change).derive(index);
-  }
-
-  ring = bcoin.keyring.fromPublic(key.publicKey, this.network);
-  ring.witness = this.witness;
-
-  if (script) {
-    // Custom redeem script.
-    assert(this.type === Account.types.PUBKEYHASH);
-    ring.script = script;
-  } else {
-    switch (this.type) {
-      case Account.types.PUBKEYHASH:
-        break;
-      case Account.types.MULTISIG:
-        keys.push(key.publicKey);
-
-        for (i = 0; i < this.keys.length; i++) {
-          shared = this.keys[i];
-          shared = shared.derive(change).derive(index);
-          keys.push(shared.publicKey);
-        }
-
-        ring.script = bcoin.script.fromMultisig(this.m, this.n, keys);
-
-        break;
-    }
-  }
-
-  if (key.privateKey)
-    ring.privateKey = key.privateKey;
-
-  ring.path = bcoin.path.fromAccount(this, ring, change, index);
-
-  return ring;
-};
-
-/**
- * Save the account to the database. Necessary
- * when address depth and keys change.
- * @param {Function} callback
- */
-
-Account.prototype.save = function save() {
-  return this.db.saveAccount(this);
-};
-
-/**
- * Save addresses to path map.
- * @param {KeyRing[]} rings
- * @param {Function} callback
- */
-
-Account.prototype.saveAddress = function saveAddress(rings, callback) {
-  return this.db.saveAddress(this.wid, rings, callback);
-};
-
-/**
- * Set change and receiving depth (depth is the index of the _next_ address).
- * Allocate all addresses up to depth. Note that this also allocates
- * new lookahead addresses.
- * @param {Number} depth
- * @param {Function} callback - Returns [Error, {@link KeyRing}, {@link KeyRing}].
- */
-
-Account.prototype.setDepth = function setDepth(receiveDepth, changeDepth, callback) {
-  var self = this;
-  var rings = [];
-  var i, receive, change;
-
-  if (receiveDepth > this.receiveDepth) {
-    for (i = this.receiveDepth; i < receiveDepth; i++) {
-      receive = this.deriveReceive(i);
-      rings.push(receive);
-    }
-
-    for (i = receiveDepth; i < receiveDepth + this.lookahead; i++)
-      rings.push(this.deriveReceive(i));
-
-    this.receiveAddress = receive;
-    this.receiveDepth = receiveDepth;
-  }
-
-  if (changeDepth > this.changeDepth) {
-    for (i = this.changeDepth; i < changeDepth; i++) {
-      change = this.deriveChange(i);
-      rings.push(change);
-    }
-
-    for (i = changeDepth; i < changeDepth + this.lookahead; i++)
-      rings.push(this.deriveChange(i));
-
-    this.changeAddress = change;
-    this.changeDepth = changeDepth;
-  }
-
-  if (rings.length === 0)
-    return callback();
-
-  this.saveAddress(rings, function(err) {
-    if (err)
-      return callback(err);
-
-    self.save();
-
-    callback(null, receive, change);
-  });
-};
-
-/**
- * Convert the account to a more inspection-friendly object.
- * @returns {Object}
- */
-
-Account.prototype.inspect = function inspect() {
-  return {
-    wid: this.wid,
-    name: this.name,
-    network: this.network,
-    initialized: this.initialized,
-    type: Account.typesByVal[this.type].toLowerCase(),
-    m: this.m,
-    n: this.n,
-    address: this.initialized
-      ? this.receiveAddress.getAddress()
-      : null,
-    programAddress: this.initialized
-      ? this.receiveAddress.getProgramAddress()
-      : null,
-    witness: this.witness,
-    accountIndex: this.accountIndex,
-    receiveDepth: this.receiveDepth,
-    changeDepth: this.changeDepth,
-    accountKey: this.accountKey.xpubkey,
-    keys: this.keys.map(function(key) {
-      return key.xpubkey;
-    })
-  };
-};
-
-/**
- * Convert the account to an object suitable for
- * serialization.
- * @returns {Object}
- */
-
-Account.prototype.toJSON = function toJSON() {
-  return {
-    network: this.network.type,
-    wid: this.wid,
-    name: this.name,
-    initialized: this.initialized,
-    type: Account.typesByVal[this.type].toLowerCase(),
-    m: this.m,
-    n: this.n,
-    witness: this.witness,
-    accountIndex: this.accountIndex,
-    receiveDepth: this.receiveDepth,
-    changeDepth: this.changeDepth,
-    receiveAddress: this.receiveAddress
-      ? this.receiveAddress.getAddress('base58')
-      : null,
-    programAddress: this.receiveAddress
-      ? this.receiveAddress.getProgramAddress('base58')
-      : null,
-    changeAddress: this.changeAddress
-      ? this.changeAddress.getAddress('base58')
-      : null,
-    accountKey: this.accountKey.xpubkey,
-    keys: this.keys.map(function(key) {
-      return key.xpubkey;
-    })
-  };
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {Object} json
- */
-
-Account.prototype.fromJSON = function fromJSON(json) {
-  var i, key;
-
-  assert.equal(json.network, this.network.type);
-  assert(utils.isNumber(json.wid));
-  assert(utils.isName(json.id), 'Bad wallet ID.');
-  assert(utils.isName(json.name), 'Bad account name.');
-  assert(typeof json.initialized === 'boolean');
-  assert(typeof json.type === 'string');
-  assert(utils.isNumber(json.m));
-  assert(utils.isNumber(json.n));
-  assert(typeof json.witness === 'boolean');
-  assert(utils.isNumber(json.accountIndex));
-  assert(utils.isNumber(json.receiveDepth));
-  assert(utils.isNumber(json.changeDepth));
-  assert(Array.isArray(json.keys));
-
-  this.wid = json.wid;
-  this.name = json.name;
-  this.initialized = json.initialized;
-  this.type = Account.types[json.type.toUpperCase()];
-  this.m = json.m;
-  this.n = json.n;
-  this.witness = json.witness;
-  this.accountIndex = json.accountIndex;
-  this.receiveDepth = json.receiveDepth;
-  this.changeDepth = json.changeDepth;
-  this.accountKey = bcoin.hd.fromBase58(json.accountKey);
-
-  assert(this.type != null);
-
-  for (i = 0; i < json.keys.length; i++) {
-    key = bcoin.hd.fromBase58(json.keys[i]);
-    this.pushKey(key);
-  }
-
-  return this;
-};
-
-/**
- * Serialize the account.
- * @returns {Buffer}
- */
-
-Account.prototype.toRaw = function toRaw(writer) {
-  var p = new BufferWriter(writer);
-  var i, key;
-
-  p.writeU32(this.network.magic);
-  p.writeVarString(this.name, 'utf8');
-  p.writeU8(this.initialized ? 1 : 0);
-  p.writeU8(this.type);
-  p.writeU8(this.m);
-  p.writeU8(this.n);
-  p.writeU8(this.witness ? 1 : 0);
-  p.writeU32(this.accountIndex);
-  p.writeU32(this.receiveDepth);
-  p.writeU32(this.changeDepth);
-  p.writeBytes(this.accountKey.toRaw());
-  p.writeU8(this.keys.length);
-
-  for (i = 0; i < this.keys.length; i++) {
-    key = this.keys[i];
-    p.writeBytes(key.toRaw());
-  }
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- * @returns {Object}
- */
-
-Account.prototype.fromRaw = function fromRaw(data) {
-  var p = new BufferReader(data);
-  var i, count, key;
-
-  this.network = bcoin.network.fromMagic(p.readU32());
-  this.name = p.readVarString('utf8');
-  this.initialized = p.readU8() === 1;
-  this.type = p.readU8();
-  this.m = p.readU8();
-  this.n = p.readU8();
-  this.witness = p.readU8() === 1;
-  this.accountIndex = p.readU32();
-  this.receiveDepth = p.readU32();
-  this.changeDepth = p.readU32();
-  this.accountKey = bcoin.hd.fromRaw(p.readBytes(82));
-
-  assert(Account.typesByVal[this.type]);
-
-  count = p.readU8();
-
-  for (i = 0; i < count; i++) {
-    key = bcoin.hd.fromRaw(p.readBytes(82));
-    this.pushKey(key);
-  }
-
-  return this;
-};
-
-/**
- * Instantiate a account from serialized data.
- * @param {WalletDB} data
- * @param {Buffer} data
- * @returns {Account}
- */
-
-Account.fromRaw = function fromRaw(db, data) {
-  return new Account(db).fromRaw(data);
-};
-
-/**
- * Instantiate a Account from a
- * jsonified account object.
- * @param {WalletDB} db
- * @param {Object} json - The jsonified account object.
- * @returns {Account}
- */
-
-Account.fromJSON = function fromJSON(db, json) {
-  return new Account(db).fromJSON(json);
-};
-
-/**
- * Test an object to see if it is a Account.
- * @param {Object} obj
- * @returns {Boolean}
- */
-
-Account.isAccount = function isAccount(obj) {
-  return obj
-    && typeof obj.receiveDepth === 'number'
-    && obj.deriveAddress === 'function';
-};
-
 /**
  * Master BIP32 key which can exist
  * in a timed out encrypted state.
@@ -3400,20 +2577,8 @@ MasterKey.isMasterKey = function isMasterKey(obj) {
     && typeof obj.decrypt === 'function';
 };
 
-/*
- * Helpers
- */
-
-function cmp(key1, key2) {
-  return key1.compare(key2);
-}
-
 /*
  * Expose
  */
 
-exports = Wallet;
-exports.Account = Account;
-exports.MasterKey = MasterKey;
-
-module.exports = exports;
+module.exports = Wallet;
diff --git a/lib/bcoin/wallet/walletdb.js b/lib/bcoin/wallet/walletdb.js
index bfb4eaa2..6c34b824 100644
--- a/lib/bcoin/wallet/walletdb.js
+++ b/lib/bcoin/wallet/walletdb.js
@@ -15,6 +15,7 @@ var constants = bcoin.constants;
 var BufferReader = require('../utils/reader');
 var BufferWriter = require('../utils/writer');
 var TXDB = require('./txdb');
+var Path = require('./path');
 var MAX_POINT = String.fromCharCode(0xdbff, 0xdfff); // U+10FFFF
 
 /*
@@ -1612,271 +1613,6 @@ WalletDB.prototype.getAddressPath = function getAddressPath(wid, hash, callback)
   });
 };
 
-/**
- * Path
- * @constructor
- * @private
- * @property {WalletID} wid
- * @property {String} name - Account name.
- * @property {Number} account - Account index.
- * @property {Number} change - Change index.
- * @property {Number} index - Address index.
- * @property {Address|null} address
- */
-
-function Path() {
-  if (!(this instanceof Path))
-    return new Path();
-
-  this.wid = null;
-  this.name = null;
-  this.account = 0;
-  this.change = -1;
-  this.index = -1;
-
-  this.encrypted = false;
-  this.imported = null;
-  this.script = null;
-
-  // Currently unused.
-  this.type = bcoin.script.types.PUBKEYHASH;
-  this.version = -1;
-
-  // Passed in by caller.
-  this.id = null;
-  this.hash = null;
-}
-
-/**
- * Clone the path object.
- * @returns {Path}
- */
-
-Path.prototype.clone = function clone() {
-  var path = new Path();
-
-  path.wid = this.wid;
-  path.name = this.name;
-  path.account = this.account;
-  path.change = this.change;
-  path.index = this.index;
-
-  path.encrypted = this.encrypted;
-  path.imported = this.imported;
-  path.script = this.script;
-
-  path.type = this.type;
-  path.version = this.version;
-
-  path.id = this.id;
-  path.hash = this.hash;
-
-  return path;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- */
-
-Path.prototype.fromRaw = function fromRaw(data) {
-  var p = new BufferReader(data);
-
-  this.wid = p.readU32();
-  this.name = p.readVarString('utf8');
-  this.account = p.readU32();
-
-  switch (p.readU8()) {
-    case 0:
-      this.change = p.readU32();
-      this.index = p.readU32();
-      if (p.readU8() === 1)
-        this.script = p.readVarBytes();
-      break;
-    case 1:
-      this.encrypted = p.readU8() === 1;
-      this.imported = p.readVarBytes();
-      this.change = -1;
-      this.index = -1;
-      break;
-    default:
-      assert(false);
-      break;
-  }
-
-  this.version = p.read8();
-  this.type = p.readU8();
-
-  return this;
-};
-
-/**
- * Instantiate path from serialized data.
- * @param {Buffer} data
- * @returns {Path}
- */
-
-Path.fromRaw = function fromRaw(data) {
-  return new Path().fromRaw(data);
-};
-
-/**
- * Serialize path.
- * @returns {Buffer}
- */
-
-Path.prototype.toRaw = function toRaw(writer) {
-  var p = new BufferWriter(writer);
-
-  p.writeU32(this.wid);
-  p.writeVarString(this.name, 'utf8');
-  p.writeU32(this.account);
-
-  if (this.index !== -1) {
-    assert(!this.imported);
-    p.writeU8(0);
-    p.writeU32(this.change);
-    p.writeU32(this.index);
-    if (this.script) {
-      p.writeU8(1);
-      p.writeVarBytes(this.script);
-    } else {
-      p.writeU8(0);
-    }
-  } else {
-    assert(this.imported);
-    p.writeU8(1);
-    p.writeU8(this.encrypted ? 1 : 0);
-    p.writeVarBytes(this.imported);
-  }
-
-  p.write8(this.version);
-  p.writeU8(this.type);
-
-  if (!writer)
-    p = p.render();
-
-  return p;
-};
-
-/**
- * Inject properties from account.
- * @private
- * @param {WalletID} wid
- * @param {KeyRing} ring
- */
-
-Path.prototype.fromAccount = function fromAccount(account, ring, change, index) {
-  this.wid = account.wid;
-  this.name = account.name;
-  this.account = account.accountIndex;
-
-  if (change != null)
-    this.change = change;
-
-  if (index != null)
-    this.index = index;
-
-  this.version = ring.witness ? 0 : -1;
-  this.type = ring.getType();
-
-  this.id = account.id;
-  this.hash = ring.getHash('hex');
-
-  return this;
-};
-
-/**
- * Instantiate path from keyring.
- * @param {WalletID} wid
- * @param {KeyRing} ring
- * @returns {Path}
- */
-
-Path.fromAccount = function fromAccount(account, ring, change, index) {
-  return new Path().fromAccount(account, ring, change, index);
-};
-
-/**
- * Convert path object to string derivation path.
- * @returns {String}
- */
-
-Path.prototype.toPath = function toPath() {
-  return 'm/' + this.account
-    + '\'/' + this.change
-    + '/' + this.index;
-};
-
-/**
- * Convert path object to an address (currently unused).
- * @returns {Address}
- */
-
-Path.prototype.toAddress = function toAddress(network) {
-  return bcoin.address.fromHash(this.hash, this.type, this.version, network);
-};
-
-/**
- * Convert path to a json-friendly object.
- * @returns {Object}
- */
-
-Path.prototype.toJSON = function toJSON() {
-  return {
-    name: this.name,
-    change: this.change === 1,
-    path: this.toPath()
-  };
-};
-
-/**
- * Inject properties from json object.
- * @private
- * @param {Object} json
- */
-
-Path.prototype.fromJSON = function fromJSON(json) {
-  var indexes = bcoin.hd.parsePath(json.path, constants.hd.MAX_INDEX);
-
-  assert(indexes.length === 3);
-  assert(indexes[0] >= constants.hd.HARDENED);
-  indexes[0] -= constants.hd.HARDENED;
-
-  this.wid = json.wid;
-  this.id = json.id;
-  this.name = json.name;
-  this.account = indexes[0];
-  this.change = indexes[1];
-  this.index = indexes[2];
-
-  return this;
-};
-
-/**
- * Instantiate path from json object.
- * @param {Object} json
- * @returns {Path}
- */
-
-Path.fromJSON = function fromJSON(json) {
-  return new Path().fromJSON(json);
-};
-
-/**
- * Inspect the path.
- * @returns {String}
- */
-
-Path.prototype.inspect = function() {
-  return '<Path: ' + this.id
-    + '(' + this.wid + ')'
-    + '/' + this.name
-    + ': ' + this.toPath()
-    + '>';
-};
-
 /**
  * Path Info
  */
@@ -2023,7 +1759,7 @@ PathInfo.prototype.toDetails = function toDetails() {
   var details = this._details;
 
   if (!details) {
-    details = new TXDB.Details(this);
+    details = new Details(this);
     this._details = details;
   }
 
@@ -2041,6 +1777,120 @@ PathInfo.prototype.toJSON = function toJSON() {
   return json;
 };
 
+/**
+ * Details
+ */
+
+function Details(info) {
+  if (!(this instanceof Details))
+    return new Details(info);
+
+  this.db = info.db;
+  this.network = info.db.network;
+  this.wid = info.wid;
+  this.id = info.id;
+  this.hash = info.tx.hash('hex');
+  this.height = info.tx.height;
+  this.block = info.tx.block;
+  this.index = info.tx.index;
+  this.confirmations = info.tx.getConfirmations(this.db.height);
+  this.fee = info.tx.getFee();
+  this.ts = info.tx.ts;
+  this.ps = info.tx.ps;
+  this.tx = info.tx;
+  this.inputs = [];
+  this.outputs = [];
+
+  this.init(info.table);
+}
+
+Details.prototype.init = function init(table) {
+  this._insert(this.tx.inputs, this.inputs, table);
+  this._insert(this.tx.outputs, this.outputs, table);
+};
+
+Details.prototype._insert = function _insert(vector, target, table) {
+  var i, j, io, address, hash, paths, path, member;
+
+  for (i = 0; i < vector.length; i++) {
+    io = vector[i];
+    member = new DetailsMember();
+
+    if (io instanceof bcoin.input)
+      member.value = io.coin ? io.coin.value : 0;
+    else
+      member.value = io.value;
+
+    address = io.getAddress();
+
+    if (address) {
+      member.address = address;
+
+      hash = address.getHash('hex');
+      paths = table[hash];
+
+      for (j = 0; j < paths.length; j++) {
+        path = paths[j];
+        if (path.wid === this.wid) {
+          path.id = this.id;
+          member.path = path;
+          break;
+        }
+      }
+    }
+
+    target.push(member);
+  }
+};
+
+Details.prototype.toJSON = function toJSON() {
+  var self = this;
+  return {
+    wid: this.wid,
+    id: this.id,
+    hash: utils.revHex(this.hash),
+    height: this.height,
+    block: this.block ? utils.revHex(this.block) : null,
+    ts: this.ts,
+    ps: this.ps,
+    index: this.index,
+    fee: utils.btc(this.fee),
+    confirmations: this.confirmations,
+    inputs: this.inputs.map(function(input) {
+      return input.toJSON(self.network);
+    }),
+    outputs: this.outputs.map(function(output) {
+      return output.toJSON(self.network);
+    }),
+    tx: this.tx.toRaw().toString('hex')
+  };
+};
+
+/**
+ * DetailsMember
+ */
+
+function DetailsMember() {
+  if (!(this instanceof DetailsMember))
+    return new DetailsMember();
+
+  this.value = 0;
+  this.address = null;
+  this.path = null;
+}
+
+DetailsMember.prototype.toJSON = function toJSON(network) {
+  return {
+    value: utils.btc(this.value),
+    address: this.address
+      ? this.address.toBase58(network)
+      : null,
+    path: this.path
+      ? this.path.toJSON()
+      : null
+  };
+};
+
 /*
  * Helpers
  */
diff --git a/lib/bcoin/workers/workers.js b/lib/bcoin/workers/workers.js
index ead7403d..5fa24bc5 100644
--- a/lib/bcoin/workers/workers.js
+++ b/lib/bcoin/workers/workers.js
@@ -828,7 +828,7 @@ Framer.item = function _item(item, writer) {
         } else if (item instanceof bcoin.keyring) {
           p.writeU8(47);
           item.toRaw(p);
-        } else if (item instanceof bcoin.hd) {
+        } else if (bcoin.hd.isHD(item)) {
           p.writeU8(48);
           p.writeBytes(item.toRaw());
         } else if (item instanceof bcoin.script) {