diff --git a/lib/bcoin/address.js b/lib/bcoin/address.js
index aa3d0581..5f43e8e3 100644
--- a/lib/bcoin/address.js
+++ b/lib/bcoin/address.js
@@ -35,7 +35,7 @@ function Address(options) {
   this.label = options.label || '';
   this.derived = !!options.derived;
 
-  this.key = bcoin.keypair(options);
+  this.key = options.pair || options.key || bcoin.keypair(options);
   this.path = options.path;
   this.change = !!options.change;
   this.index = options.index;
diff --git a/lib/bcoin/hd.js b/lib/bcoin/hd.js
index fe21186d..f32385d1 100644
--- a/lib/bcoin/hd.js
+++ b/lib/bcoin/hd.js
@@ -46,8 +46,6 @@
  * THE SOFTWARE.
  */
 
-var hd = exports;
-
 /**
  * Modules
  */
@@ -55,6 +53,7 @@ var hd = exports;
 var bcoin = require('../bcoin');
 var hash = require('hash.js');
 var bn = require('bn.js');
+var inherits = require('inherits');
 var elliptic = require('elliptic');
 var utils = bcoin.utils;
 var assert = utils.assert;
@@ -104,6 +103,14 @@ HDSeed._mnemonic = function _mnemonic(entropy) {
   return mnemonic.join(' ');
 };
 
+/**
+ * Abstract
+ */
+
+function HD(options) {
+  return new HDPrivateKey(options);
+}
+
 /**
  * HD Private Key
  */
@@ -114,15 +121,30 @@ function HDPrivateKey(options) {
   if (!(this instanceof HDPrivateKey))
     return new HDPrivateKey(options);
 
+  assert(!(options instanceof HDPrivateKey));
+  assert(!(options instanceof HDPublicKey));
+
+  if (options instanceof bcoin.hd.seed)
+    options = { seed: options };
+
+  if (options) {
+    if (options.xprivkey)
+      options.xkey = options.xprivkey;
+    if (options.xpubkey)
+      options.xkey = options.xpubkey;
+  }
+
+  if (options) {
+    if (HDPublicKey.isExtended(options) || HDPublicKey.isExtended(options.xkey))
+      return new HDPublicKey(options);
+  }
+
   if (!options)
     options = { seed: bcoin.hd.seed() };
 
   if (HDPrivateKey.isExtended(options))
     options = { xkey: options };
 
-  if (HDPublicKey.isExtended(options))
-    return new HDPublicKey(options);
-
   if (options.passphrase !== undefined
       || options.bits
       || options.entropy
@@ -161,6 +183,8 @@ function HDPrivateKey(options) {
   this.isPublic = false;
 }
 
+inherits(HDPrivateKey, HD);
+
 HDPrivateKey.prototype.scan44 = function scan44(options, txByAddress, callback) {
   var self = this;
   var accounts = [];
@@ -837,9 +861,20 @@ function HDPublicKey(options) {
   if (!options)
     throw new Error('No options for HDPublicKey');
 
+  assert(!(options instanceof HDPrivateKey));
+  assert(!(options instanceof HDPublicKey));
+
+  assert(!options.xprivkey);
+
+  if (options.xpubkey)
+    options.xkey = options.xpubkey;
+
   if (HDPublicKey.isExtended(options))
     options = { xkey: options };
 
+  if (HDPrivateKey.isExtended(options) || HDPrivateKey.isExtended(options.xkey))
+    throw new Error('Cannot pass xprivkey into HDPublicKey');
+
   data = options.xkey
     ? this._unbuild(options.xkey)
     : options;
@@ -859,6 +894,8 @@ function HDPublicKey(options) {
   this.isPublic = true;
 }
 
+inherits(HDPublicKey, HD);
+
 HDPublicKey.prototype.scan44 = HDPrivateKey.prototype.scan44;
 HDPublicKey.prototype.deriveAccount44 = HDPrivateKey.prototype.deriveAccount44;
 HDPublicKey.prototype.deriveBIP44 = HDPrivateKey.prototype.deriveBIP44;
@@ -1174,10 +1211,14 @@ cache.get = function(key, index) {
  * Expose
  */
 
-hd.seed = HDSeed;
-hd.priv = HDPrivateKey;
-hd.pub = HDPublicKey;
-hd.privateKey = HDPrivateKey;
-hd.publicKey = HDPublicKey;
-hd.pbkdf2 = pbkdf2;
-hd.fromJSON = HDPrivateKey.fromJSON;
+exports = HD;
+
+exports.seed = HDSeed;
+exports.priv = HDPrivateKey;
+exports.pub = HDPublicKey;
+exports.privateKey = HDPrivateKey;
+exports.publicKey = HDPublicKey;
+exports.pbkdf2 = pbkdf2;
+exports.fromJSON = HDPrivateKey.fromJSON;
+
+module.exports = HD;
diff --git a/lib/bcoin/wallet.js b/lib/bcoin/wallet.js
index 07c356fa..aa94120a 100644
--- a/lib/bcoin/wallet.js
+++ b/lib/bcoin/wallet.js
@@ -31,39 +31,17 @@ function Wallet(options) {
 
   options = utils.merge({}, options);
 
-  if (!options.master) {
-    options.master = options.hd
-      ? bcoin.hd.privateKey(options.hd)
-      : bcoin.hd.privateKey();
-    delete options.hd;
+  if (typeof options.master === 'string')
+    options.master = { xkey: options.master };
+
+  if (options.master
+      && typeof options.master === 'object'
+      && !(options.master instanceof bcoin.hd)) {
+    options.master = bcoin.hd(options.master);
   }
 
-  if (options.key) {
-    options.pair = options.key;
-    delete options.key;
-  }
-
-  if (options.priv) {
-    options.privateKey = options.priv;
-    delete options.priv;
-  }
-
-  if (options.pub) {
-    options.publicKey = options.pub;
-    delete options.pub;
-  }
-
-  if ((options.pair instanceof bcoin.hd.privateKey)
-      || (options.pair instanceof bcoin.hd.publicKey)) {
-    options.master = options.pair;
-    delete options.pair;
-  } else if (options.privateKey instanceof bcoin.hd.privateKey) {
-    options.master = options.privateKey;
-    delete options.privateKey;
-  } else if (options.publicKey instanceof bcoin.hd.publicKey) {
-    options.master = options.publicKey;
-    delete options.publicKey;
-  }
+  if (!options.master)
+    options.master = bcoin.hd.privateKey();
 
   this.options = options;
   this.addresses = [];
@@ -81,7 +59,7 @@ function Wallet(options) {
   this.cosignerIndex = -1;
 
   this.type = options.type || 'pubkeyhash';
-  this.derivation = options.derivation || null;
+  this.derivation = options.derivation || 'bip44';
   this.compressed = options.compressed !== false;
   this.keys = [];
   this.m = options.m || 1;
@@ -93,13 +71,6 @@ function Wallet(options) {
   assert(this.type === 'pubkeyhash' || this.type === 'multisig');
   this.prefixType = this.type === 'multisig' ? 'scripthash' : 'pubkeyhash';
 
-  if (!this.derivation) {
-    if (this.type === 'multisig')
-      this.derivation = 'bip45';
-    else
-      this.derivation = 'bip44';
-  }
-
   if (network.prefixes[this.prefixType] == null)
     throw new Error('Unknown prefix: ' + this.prefixType);
 
@@ -778,7 +749,6 @@ Wallet.prototype.__defineGetter__('address', function() {
 });
 
 Wallet.prototype.toJSON = function toJSON(encrypt) {
-  assert(this._initialized);
   return {
     v: 3,
     name: 'wallet',