diff --git a/lib/hd/hd.js b/lib/hd/hd.js
index ce200a51..aeca5a2c 100644
--- a/lib/hd/hd.js
+++ b/lib/hd/hd.js
@@ -82,25 +82,14 @@ HD.fromJSON = function fromJSON(json, network) {
 /**
  * Instantiate an HD key from serialized data.
  * @param {Buffer} data
+ * @param {Network?} network
  * @returns {HDPrivateKey|HDPublicKey}
  */
 
-HD.fromRaw = function fromRaw(data) {
-  if (HDPrivateKey.isRaw(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.isRaw(data))
-    return HDPrivateKey.fromExtended(data);
-  return HDPublicKey.fromRaw(data);
+HD.fromRaw = function fromRaw(data, network) {
+  if (HDPrivateKey.isRaw(data, network))
+    return HDPrivateKey.fromRaw(data, network);
+  return HDPublicKey.fromRaw(data, network);
 };
 
 /**
@@ -117,11 +106,11 @@ HD.from = function from(options, network) {
   if (HD.isHD(options))
     return options;
 
-  if (HD.isBase58(options))
+  if (HD.isBase58(options, network))
     return HD.fromBase58(options, network);
 
-  if (HD.isRaw(options))
-    return HD.fromRaw(options);
+  if (HD.isRaw(options, network))
+    return HD.fromRaw(options, network);
 
   if (options && typeof options === 'object')
     return HD.fromMnemonic(options, network);
@@ -132,23 +121,25 @@ HD.from = function from(options, network) {
 /**
  * Test whether an object is in the form of a base58 hd key.
  * @param {String} data
+ * @param {Network?} network
  * @returns {Boolean}
  */
 
-HD.isBase58 = function isBase58(data) {
-  return HDPrivateKey.isBase58(data)
-    || HDPublicKey.isBase58(data);
+HD.isBase58 = function isBase58(data, network) {
+  return HDPrivateKey.isBase58(data, network)
+    || HDPublicKey.isBase58(data, network);
 };
 
 /**
  * Test whether an object is in the form of a serialized hd key.
  * @param {Buffer} data
+ * @param {Network?} network
  * @returns {NetworkType}
  */
 
-HD.isRaw = function isRaw(data) {
-  return HDPrivateKey.isRaw(data)
-    || HDPublicKey.isRaw(data);
+HD.isRaw = function isRaw(data, network) {
+  return HDPrivateKey.isRaw(data, network)
+    || HDPublicKey.isRaw(data, network);
 };
 
 /**
diff --git a/lib/hd/private.js b/lib/hd/private.js
index df4bc3d2..40164ff1 100644
--- a/lib/hd/private.js
+++ b/lib/hd/private.js
@@ -10,7 +10,6 @@ var assert = require('assert');
 var util = require('../utils/util');
 var crypto = require('../crypto/crypto');
 var ec = require('../crypto/ec');
-var networks = require('../protocol/networks');
 var Network = require('../protocol/network');
 var StaticWriter = require('../utils/staticwriter');
 var BufferReader = require('../utils/reader');
@@ -142,18 +141,6 @@ HDPrivateKey.prototype.xpubkey = function xpubkey() {
   return this.toPublic().xpubkey();
 };
 
-/**
- * Verify network.
- * @param {(NetworkType|Network)} network
- * @returns {Boolean}
- */
-
-HDPrivateKey.prototype.verifyNetwork = function verifyNetwork(network) {
-  network = Network.get(network);
-  return this.network.keyPrefix.xprivkey === network.keyPrefix.xprivkey
-    && this.network.keyPrefix.coinType === network.keyPrefix.coinType;
-};
-
 /**
  * Destroy the key (zeroes chain code, privkey, and pubkey).
  * @param {Boolean} pub - Destroy hd public key as well.
@@ -189,19 +176,11 @@ HDPrivateKey.prototype.destroy = function destroy(pub) {
  * @returns {HDPrivateKey}
  */
 
-HDPrivateKey.prototype.derive = function derive(index, hardened, cache) {
+HDPrivateKey.prototype.derive = function derive(index, hardened) {
   var bw, id, data, hash, left, right, key, child;
 
-  if (typeof hardened !== 'boolean') {
-    cache = hardened;
-    hardened = false;
-  }
-
-  if (!cache)
-    cache = common.cache;
-
   if (typeof index === 'string')
-    return this.derivePath(index, cache);
+    return this.derivePath(index);
 
   hardened = index >= common.HARDENED ? true : hardened;
 
@@ -214,12 +193,11 @@ HDPrivateKey.prototype.derive = function derive(index, hardened, cache) {
   if (this.depth >= 0xff)
     throw new Error('Depth too high.');
 
-  if (cache) {
-    id = this.getID(index);
-    child = cache.get(id);
-    if (child)
-      return child;
-  }
+  id = this.getID(index);
+  child = common.cache.get(id);
+
+  if (child)
+    return child;
 
   bw = new StaticWriter(37);
 
@@ -241,7 +219,7 @@ HDPrivateKey.prototype.derive = function derive(index, hardened, cache) {
   try {
     key = ec.privateKeyTweakAdd(this.privateKey, left);
   } catch (e) {
-    return this.derive(index + 1, cache);
+    return this.derive(index + 1);
   }
 
   if (!this.fingerPrint)
@@ -256,8 +234,7 @@ HDPrivateKey.prototype.derive = function derive(index, hardened, cache) {
   child.privateKey = key;
   child.publicKey = ec.publicKeyCreate(key, true);
 
-  if (cache)
-    cache.set(id, child);
+  common.cache.set(id, child);
 
   return child;
 };
@@ -282,13 +259,13 @@ HDPrivateKey.prototype.getID = function getID(index) {
  * @throws Error if key is not a master key.
  */
 
-HDPrivateKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex, cache) {
+HDPrivateKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex) {
   assert(util.isNumber(accountIndex), 'Account index must be a number.');
   assert(this.isMaster(), 'Cannot derive account index.');
   return this
-    .derive(44, true, cache)
-    .derive(this.network.keyPrefix.coinType, true, cache)
-    .derive(accountIndex, true, cache);
+    .derive(44, true)
+    .derive(this.network.keyPrefix.coinType, true)
+    .derive(accountIndex, true);
 };
 
 /**
@@ -296,9 +273,9 @@ HDPrivateKey.prototype.deriveAccount44 = function deriveAccount44(accountIndex,
  * @returns {HDPrivateKey}
  */
 
-HDPrivateKey.prototype.derivePurpose45 = function derivePurpose45(cache) {
+HDPrivateKey.prototype.derivePurpose45 = function derivePurpose45() {
   assert(this.isMaster(), 'Cannot derive purpose 45.');
-  return this.derive(45, true, cache);
+  return this.derive(45, true);
 };
 
 /**
@@ -332,33 +309,38 @@ HDPrivateKey.prototype.isPurpose45 = function isPurpose45() {
 /**
  * Test whether an object is in the form of a base58 xprivkey.
  * @param {String} data
+ * @param {Network?} network
  * @returns {Boolean}
  */
 
-HDPrivateKey.isBase58 = function isBase58(data) {
-  var i, type, prefix;
+HDPrivateKey.isBase58 = function isBase58(data, network) {
+  var 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;
-  }
+  if (data.length < 4)
+    return false;
 
-  return false;
+  prefix = data.substring(0, 4);
+
+  try {
+    Network.fromPrivate58(prefix, network);
+    return true;
+  } catch (e) {
+    return false;
+  }
 };
 
 /**
  * Test whether a buffer has a valid network prefix.
  * @param {Buffer} data
- * @returns {NetworkType}
+ * @param {Network?} network
+ * @returns {Boolean}
  */
 
-HDPrivateKey.isRaw = function isRaw(data) {
-  var i, version, prefix, type;
+HDPrivateKey.isRaw = function isRaw(data, network) {
+  var version;
 
   if (!Buffer.isBuffer(data))
     return false;
@@ -368,14 +350,12 @@ HDPrivateKey.isRaw = function isRaw(data) {
 
   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;
+  try {
+    Network.fromPrivate(version, network);
+    return true;
+  } catch (e) {
+    return false;
   }
-
-  return false;
 };
 
 /**
@@ -404,13 +384,13 @@ HDPrivateKey.isValidPath = function isValidPath(path) {
  * @throws Error if `path` is not a valid path.
  */
 
-HDPrivateKey.prototype.derivePath = function derivePath(path, cache) {
+HDPrivateKey.prototype.derivePath = function derivePath(path) {
   var indexes = common.parsePath(path, common.MAX_INDEX);
   var key = this;
   var i;
 
   for (i = 0; i < indexes.length; i++)
-    key = key.derive(indexes[i], cache);
+    key = key.derive(indexes[i]);
 
   return key;
 };
@@ -530,8 +510,7 @@ HDPrivateKey.fromSeed = function fromSeed(seed, network) {
 
 HDPrivateKey.prototype.fromMnemonic = function fromMnemonic(mnemonic, network) {
   assert(mnemonic instanceof Mnemonic);
-  this.fromSeed(mnemonic.toSeed(), network);
-  return this;
+  return this.fromSeed(mnemonic.toSeed(), network);
 };
 
 /**
@@ -622,42 +601,31 @@ HDPrivateKey.generate = function generate(network) {
  */
 
 HDPrivateKey.prototype.fromBase58 = function fromBase58(xkey, network) {
-  this.fromRaw(base58.decode(xkey));
+  assert(typeof xkey === 'string');
   this._xprivkey = xkey;
-  if (network && !this.verifyNetwork(network))
-    throw new Error('Network mismatch for HD private key.');
-  return this;
+  return this.fromRaw(base58.decode(xkey), network);
 };
 
 /**
  * Inject properties from serialized data.
  * @private
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  */
 
-HDPrivateKey.prototype.fromReader = function fromReader(br) {
-  var i, version, type, prefix;
+HDPrivateKey.prototype.fromReader = function fromReader(br, network) {
+  var version = br.readU32BE();
 
-  version = br.readU32BE();
+  this.network = Network.fromPrivate(version, network);
   this.depth = br.readU8();
   this.parentFingerPrint = br.readBytes(4);
   this.childIndex = br.readU32BE();
   this.chainCode = br.readBytes(32);
   br.readU8();
   this.privateKey = br.readBytes(32);
-  br.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 = Network.get(type);
+
+  br.verifyChecksum();
 
   return this;
 };
@@ -666,10 +634,11 @@ HDPrivateKey.prototype.fromReader = function fromReader(br) {
  * Inject properties from serialized data.
  * @private
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  */
 
-HDPrivateKey.prototype.fromRaw = function fromRaw(raw) {
-  return this.fromReader(new BufferReader(raw));
+HDPrivateKey.prototype.fromRaw = function fromRaw(raw, network) {
+  return this.fromReader(new BufferReader(raw), network);
 };
 
 /**
@@ -739,21 +708,23 @@ HDPrivateKey.fromBase58 = function fromBase58(xkey, network) {
 /**
  * Instantiate key from buffer reader.
  * @param {BufferReader} br
+ * @param {(Network|NetworkType)?} network
  * @returns {HDPrivateKey}
  */
 
-HDPrivateKey.fromReader = function fromReader(br) {
-  return new HDPrivateKey().fromReader(br);
+HDPrivateKey.fromReader = function fromReader(br, network) {
+  return new HDPrivateKey().fromReader(br, network);
 };
 
 /**
  * Instantiate key from serialized data.
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  * @returns {HDPrivateKey}
  */
 
-HDPrivateKey.fromRaw = function fromRaw(raw) {
-  return new HDPrivateKey().fromRaw(raw);
+HDPrivateKey.fromRaw = function fromRaw(raw, network) {
+  return new HDPrivateKey().fromRaw(raw, network);
 };
 
 /**
@@ -803,7 +774,7 @@ HDPrivateKey.isHDPrivateKey = function isHDPrivateKey(obj) {
   return obj
     && typeof obj.derive === 'function'
     && typeof obj.fromMnemonic === 'function'
-    && obj.chainCode !== undefined;
+    && Buffer.isBuffer(obj.chainCode);
 };
 
 /*
diff --git a/lib/hd/public.js b/lib/hd/public.js
index a14c1889..9b782ca1 100644
--- a/lib/hd/public.js
+++ b/lib/hd/public.js
@@ -10,7 +10,6 @@ var assert = require('assert');
 var util = require('../utils/util');
 var crypto = require('../crypto/crypto');
 var ec = require('../crypto/ec');
-var networks = require('../protocol/networks');
 var Network = require('../protocol/network');
 var StaticWriter = require('../utils/staticwriter');
 var BufferReader = require('../utils/reader');
@@ -121,18 +120,6 @@ HDPublicKey.prototype.xpubkey = function() {
   return this._xpubkey;
 };
 
-/**
- * Verify network.
- * @param {(NetworkType|Network)} network
- * @returns {Boolean}
- */
-
-HDPublicKey.prototype.verifyNetwork = function verifyNetwork(network) {
-  network = Network.get(network);
-  return this.network.keyPrefix.xpubkey === network.keyPrefix.xpubkey
-    && this.network.keyPrefix.coinType === network.keyPrefix.coinType;
-};
-
 /**
  * Destroy the key (zeroes chain code and pubkey).
  */
@@ -162,19 +149,11 @@ HDPublicKey.prototype.destroy = function destroy() {
  * @throws on `hardened`
  */
 
-HDPublicKey.prototype.derive = function derive(index, hardened, cache) {
+HDPublicKey.prototype.derive = function derive(index, hardened) {
   var bw, id, data, hash, left, right, key, child;
 
-  if (typeof hardened !== 'boolean') {
-    cache = hardened;
-    hardened = false;
-  }
-
-  if (!cache)
-    cache = common.cache;
-
   if (typeof index === 'string')
-    return this.derivePath(index, cache);
+    return this.derivePath(index);
 
   if (index >= common.HARDENED || hardened)
     throw new Error('Index out of range.');
@@ -185,12 +164,11 @@ HDPublicKey.prototype.derive = function derive(index, hardened, cache) {
   if (this.depth >= 0xff)
     throw new Error('Depth too high.');
 
-  if (cache) {
-    id = this.getID(index);
-    child = cache.get(id);
-    if (child)
-      return child;
-  }
+  id = this.getID(index);
+  child = common.cache.get(id);
+
+  if (child)
+    return child;
 
   bw = new StaticWriter(37);
   bw.writeBytes(this.publicKey);
@@ -204,7 +182,7 @@ HDPublicKey.prototype.derive = function derive(index, hardened, cache) {
   try {
     key = ec.publicKeyTweakAdd(this.publicKey, left, true);
   } catch (e) {
-    return this.derive(index + 1, cache);
+    return this.derive(index + 1);
   }
 
   if (!this.fingerPrint)
@@ -218,8 +196,7 @@ HDPublicKey.prototype.derive = function derive(index, hardened, cache) {
   child.chainCode = right;
   child.publicKey = key;
 
-  if (cache)
-    cache.set(id, child);
+  common.cache.set(id, child);
 
   return child;
 };
@@ -320,13 +297,13 @@ HDPublicKey.isValidPath = function isValidPath(path) {
  * @throws Error if hardened.
  */
 
-HDPublicKey.prototype.derivePath = function derivePath(path, cache) {
+HDPublicKey.prototype.derivePath = function derivePath(path) {
   var indexes = common.parsePath(path, common.HARDENED);
   var key = this;
   var i;
 
   for (i = 0; i < indexes.length; i++)
-    key = key.derive(indexes[i], cache);
+    key = key.derive(indexes[i]);
 
   return key;
 };
@@ -427,47 +404,53 @@ HDPublicKey.fromJSON = function fromJSON(json, network) {
 /**
  * Test whether an object is in the form of a base58 xpubkey.
  * @param {String} data
+ * @param {(Network|NetworkType)?} network
  * @returns {Boolean}
  */
 
-HDPublicKey.isBase58 = function isBase58(data) {
-  var i, type, prefix;
+HDPublicKey.isBase58 = function isBase58(data, network) {
+  var 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;
-  }
+  if (data.length < 4)
+    return false;
 
-  return false;
+  prefix = data.substring(0, 4);
+
+  try {
+    Network.fromPublic58(prefix, network);
+    return true;
+  } catch (e) {
+    return false;
+  }
 };
 
 /**
  * Test whether a buffer has a valid network prefix.
  * @param {Buffer} data
+ * @param {(Network|NetworkType)?} network
  * @returns {NetworkType}
  */
 
-HDPublicKey.isRaw = function isRaw(data) {
-  var i, version, prefix, type;
+HDPublicKey.isRaw = function isRaw(data, network) {
+  var version;
 
   if (!Buffer.isBuffer(data))
     return false;
 
+  if (data.length < 4)
+    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;
+  try {
+    Network.fromPublic(version, network);
+    return true;
+  } catch (e) {
+    return false;
   }
-
-  return false;
 };
 
 /**
@@ -478,41 +461,30 @@ HDPublicKey.isRaw = function isRaw(data) {
  */
 
 HDPublicKey.prototype.fromBase58 = function fromBase58(xkey, network) {
-  this.fromRaw(base58.decode(xkey));
+  assert(typeof xkey === 'string');
   this._xpubkey = xkey;
-  if (network && !this.verifyNetwork(network))
-    throw new Error('Network mismatch for HD public key.');
-  return this;
+  return this.fromRaw(base58.decode(xkey), network);
 };
 
 /**
  * Inject properties from serialized data.
  * @private
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  */
 
-HDPublicKey.prototype.fromReader = function fromReader(br) {
-  var i, version, type, prefix;
+HDPublicKey.prototype.fromReader = function fromReader(br, network) {
+  var version = br.readU32BE();
 
-  version = br.readU32BE();
+  this.network = Network.fromPublic(version, network);
   this.depth = br.readU8();
   this.parentFingerPrint = br.readBytes(4);
   this.childIndex = br.readU32BE();
   this.chainCode = br.readBytes(32);
   this.publicKey = br.readBytes(33);
+
   br.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 = Network.get(type);
-
   return this;
 };
 
@@ -520,15 +492,16 @@ HDPublicKey.prototype.fromReader = function fromReader(br) {
  * Inject properties from serialized data.
  * @private
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  */
 
-HDPublicKey.prototype.fromRaw = function fromRaw(raw) {
-  return this.fromReader(new BufferReader(raw));
+HDPublicKey.prototype.fromRaw = function fromRaw(raw, network) {
+  return this.fromReader(new BufferReader(raw), network);
 };
 
 /**
  * Serialize key data to base58 extended key.
- * @param {Network|String} network
+ * @param {(Network|NetworkType)?} network
  * @returns {Base58String}
  */
 
@@ -539,7 +512,7 @@ HDPublicKey.prototype.toBase58 = function toBase58(network) {
 /**
  * Write the key to a buffer writer.
  * @param {BufferWriter} bw
- * @param {Network|NetworkType} network
+ * @param {(Network|NetworkType)?} network
  */
 
 HDPublicKey.prototype.toWriter = function toWriter(bw, network) {
@@ -570,7 +543,7 @@ HDPublicKey.prototype.getSize = function getSize() {
 
 /**
  * Serialize the key.
- * @param {Network|NetworkType} network
+ * @param {(Network|NetworkType)?} network
  * @returns {Buffer}
  */
 
@@ -592,21 +565,23 @@ HDPublicKey.fromBase58 = function fromBase58(xkey, network) {
 /**
  * Instantiate key from serialized data.
  * @param {BufferReader} br
+ * @param {(Network|NetworkType)?} network
  * @returns {HDPublicKey}
  */
 
-HDPublicKey.fromReader = function fromReader(br) {
-  return new HDPublicKey().fromReader(br);
+HDPublicKey.fromReader = function fromReader(br, network) {
+  return new HDPublicKey().fromReader(br, network);
 };
 
 /**
  * Instantiate key from serialized data.
  * @param {Buffer} raw
+ * @param {(Network|NetworkType)?} network
  * @returns {HDPublicKey}
  */
 
-HDPublicKey.fromRaw = function fromRaw(data) {
-  return new HDPublicKey().fromRaw(data);
+HDPublicKey.fromRaw = function fromRaw(data, network) {
+  return new HDPublicKey().fromRaw(data, network);
 };
 
 /**
@@ -618,8 +593,8 @@ HDPublicKey.fromRaw = function fromRaw(data) {
 HDPublicKey.isHDPublicKey = function isHDPublicKey(obj) {
   return obj
     && typeof obj.derive === 'function'
-    && typeof obj.toExtended !== 'function'
-    && obj.chainCode !== undefined;
+    && obj.fromMnemonic === undefined
+    && Buffer.isBuffer(obj.chainCode);
 };
 
 /*
diff --git a/lib/primitives/address.js b/lib/primitives/address.js
index c29a44b2..58782091 100644
--- a/lib/primitives/address.js
+++ b/lib/primitives/address.js
@@ -9,7 +9,6 @@
 
 var assert = require('assert');
 var Network = require('../protocol/network');
-var networks = require('../protocol/networks');
 var encoding = require('../utils/encoding');
 var util = require('../utils/util');
 var crypto = require('../crypto/crypto');
@@ -22,12 +21,7 @@ var bech32 = require('../utils/bech32');
  * Represents an address.
  * @alias module:primitives.Address
  * @constructor
- * @param {Object} options
- * @param {Buffer|Hash} options.hash - Address hash.
- * @param {AddressPrefix} options.type - Address type
- * `{witness,}{pubkeyhash,scripthash}`.
- * @param {Number} [options.version=-1] - Witness program version.
- * @param {(Network|NetworkType)?} options.network - Network name.
+ * @param {Object?} options
  * @property {Buffer} hash
  * @property {AddressPrefix} type
  * @property {Number} version
@@ -105,30 +99,6 @@ Address.prototype.getHash = function getHash(enc) {
   return this.hash;
 };
 
-/**
- * Get a network address prefix for the address.
- * @param {Network?} network
- * @returns {Number}
- */
-
-Address.prototype.getPrefix = function getPrefix(network) {
-  if (!network)
-    network = this.network;
-  network = Network.get(network);
-  return Address.getPrefix(this.type, this.hash, network);
-};
-
-/**
- * Verify an address network (compares prefixes).
- * @param {Network} network
- * @returns {Boolean}
- */
-
-Address.prototype.verifyNetwork = function verifyNetwork(network) {
-  assert(network);
-  return this.getPrefix() === this.getPrefix(network);
-};
-
 /**
  * Test whether the address is null.
  * @returns {Boolean}
@@ -153,13 +123,46 @@ Address.prototype.isNull = function isNull() {
 
 /**
  * Get the address type as a string.
- * @returns {AddressPrefix}
+ * @returns {String}
  */
 
 Address.prototype.getType = function getType() {
   return Address.typesByVal[this.type].toLowerCase();
 };
 
+/**
+ * Get a network address prefix for the address.
+ * @param {Network?} network
+ * @returns {Number}
+ */
+
+Address.prototype.getPrefix = function getPrefix(network) {
+  var prefixes;
+
+  if (!network)
+    network = this.network;
+
+  network = Network.get(network);
+  prefixes = network.addressPrefix;
+
+  switch (this.type) {
+    case Address.types.PUBKEYHASH:
+      return prefixes.pubkeyhash;
+    case Address.types.SCRIPTHASH:
+      return prefixes.scripthash;
+    case Address.types.WITNESS:
+      if (this.hash.length === 20)
+        return prefixes.witnesspubkeyhash;
+
+      if (this.hash.length === 32)
+        return prefixes.witnessscripthash;
+
+      break;
+  }
+
+  return -1;
+};
+
 /**
  * Calculate size of serialized address.
  * @returns {Number}
@@ -225,7 +228,7 @@ Address.prototype.toBech32 = function toBech32(network) {
   var hrp;
 
   assert(version !== -1,
-    'Cannot convert non-segwit address to bech32.');
+    'Cannot convert non-program address to bech32.');
 
   if (!network)
     network = this.network;
@@ -245,28 +248,18 @@ Address.prototype.toBech32 = function toBech32(network) {
  */
 
 Address.prototype.fromString = function fromString(addr, network) {
-  var i, type, hrp, expect;
+  var hrp;
 
   assert(typeof addr === 'string');
-  assert(addr.length >= 2);
 
-  hrp = addr.substring(0, 2).toLowerCase();
-
-  if (network) {
-    network = Network.get(network);
-    expect = network.addressPrefix.bech32;
-    if (hrp === expect)
-      return this.fromBech32(addr, network);
-  } else {
-    for (i = 0; i < networks.types.length; i++) {
-      type = networks.types[i];
-      expect = networks[type].addressPrefix.bech32;
-      if (hrp === expect)
-        return this.fromBech32(addr, type);
-    }
+  try {
+    hrp = addr.substring(0, 2).toLowerCase();
+    network = Network.fromBech32(hrp, network);
+  } catch (e) {
+    return this.fromBase58(addr, network);
   }
 
-  return this.fromBase58(addr, network);
+  return this.fromBech32(addr, network);
 };
 
 /**
@@ -312,23 +305,16 @@ Address.prototype.inspect = function inspect() {
  * @throws Parse error
  */
 
-Address.prototype.fromRaw = function fromRaw(data) {
+Address.prototype.fromRaw = function fromRaw(data, network) {
   var br = new BufferReader(data, true);
-  var i, prefix, network, type, version, hash;
+  var prefix, type, version, hash;
 
   if (data.length > 40)
     throw new Error('Address is too long.');
 
   prefix = br.readU8();
-
-  for (i = 0; i < networks.types.length; i++) {
-    network = networks[networks.types[i]];
-    type = Address.getType(prefix, network);
-    if (type !== -1)
-      break;
-  }
-
-  assert(i < networks.types.length, 'Unknown address prefix.');
+  network = Network.fromAddress(prefix, network);
+  type = Address.getType(prefix, network);
 
   if (data.length > 25) {
     version = br.readU8();
@@ -351,87 +337,69 @@ Address.prototype.fromRaw = function fromRaw(data) {
  * @throws Parse error.
  */
 
-Address.fromRaw = function fromRaw(data) {
-  return new Address().fromRaw(data);
+Address.fromRaw = function fromRaw(data, network) {
+  return new Address().fromRaw(data, network);
 };
 
 /**
  * Inject properties from base58 address.
  * @private
- * @param {Base58Address} str
+ * @param {Base58Address} data
  * @param {Network?} network
  * @throws Parse error
  */
 
-Address.prototype.fromBase58 = function fromBase58(str, network) {
-  assert(typeof str === 'string');
+Address.prototype.fromBase58 = function fromBase58(data, network) {
+  assert(typeof data === 'string');
 
-  if (str.length > 55)
+  if (data.length > 55)
     throw new Error('Address is too long.');
 
-  this.fromRaw(base58.decode(str));
-
-  if (network && !this.verifyNetwork(network))
-    throw new Error('Network mismatch for address.');
-
-  return this;
+  return this.fromRaw(base58.decode(data), network);
 };
 
 /**
  * Create an address object from a base58 address.
- * @param {Base58Address} str
+ * @param {Base58Address} data
  * @param {Network?} network
  * @returns {Address}
  * @throws Parse error.
  */
 
-Address.fromBase58 = function fromBase58(str, network) {
-  return new Address().fromBase58(str, network);
+Address.fromBase58 = function fromBase58(data, network) {
+  return new Address().fromBase58(data, network);
 };
 
 /**
  * Inject properties from bech32 address.
  * @private
- * @param {String} str
+ * @param {String} data
  * @param {Network?} network
  * @throws Parse error
  */
 
-Address.prototype.fromBech32 = function fromBech32(str, network) {
+Address.prototype.fromBech32 = function fromBech32(data, network) {
   var type = Address.types.WITNESS;
-  var i, addr;
+  var addr;
 
-  assert(typeof str === 'string');
+  assert(typeof data === 'string');
 
-  addr = bech32.decode(str);
+  addr = bech32.decode(data);
+  network = Network.fromBech32(addr.hrp, network);
 
-  if (network) {
-    network = Network.get(network);
-    if (addr.hrp !== network.addressPrefix.bech32)
-      throw new Error('Network mismatch for bech32 address.');
-  } else {
-    for (i = 0; i < networks.types.length; i++) {
-      network = networks[networks.types[i]];
-      if (addr.hrp === network.addressPrefix.bech32)
-        break;
-    }
-
-    assert(i < networks.types.length, 'Unknown bech32 address prefix.');
-  }
-
-  return this.fromHash(addr.hash, type, addr.version, network.type);
+  return this.fromHash(addr.hash, type, addr.version, network);
 };
 
 /**
  * Create an address object from a bech32 address.
- * @param {String} str
+ * @param {String} data
  * @param {Network?} network
  * @returns {Address}
  * @throws Parse error.
  */
 
-Address.fromBech32 = function fromBech32(str, network) {
-  return new Address().fromBech32(str, network);
+Address.fromBech32 = function fromBech32(data, network) {
+  return new Address().fromBech32(data, network);
 };
 
 /**
@@ -877,37 +845,11 @@ Address.getHash = function getHash(data, enc) {
     : hash;
 };
 
-/**
- * Get a network address prefix for a specified address type.
- * @param {AddressPrefix} type
- * @param {Buffer} hash
- * @param {Network} network
- * @returns {Number}
- */
-
-Address.getPrefix = function getPrefix(type, hash, network) {
-  var prefixes = network.addressPrefix;
-  switch (type) {
-    case Address.types.PUBKEYHASH:
-      return prefixes.pubkeyhash;
-    case Address.types.SCRIPTHASH:
-      return prefixes.scripthash;
-    case Address.types.WITNESS:
-      if (hash.length === 20)
-        return prefixes.witnesspubkeyhash;
-      if (hash.length === 32)
-        return prefixes.witnessscripthash;
-      assert(false, 'No witness prefix defined.');
-    default:
-      return -1;
-  }
-};
-
 /**
  * Get an address type for a specified network address prefix.
  * @param {Number} prefix
  * @param {Network} network
- * @returns {AddressPrefix}
+ * @returns {AddressType}
  */
 
 Address.getType = function getType(prefix, network) {
@@ -922,7 +864,7 @@ Address.getType = function getType(prefix, network) {
     case prefixes.witnessscripthash:
       return Address.types.WITNESS;
     default:
-      return -1;
+      throw new Error('Unknown address prefix.');
   }
 };
 
diff --git a/lib/primitives/keyring.js b/lib/primitives/keyring.js
index f96f8fb8..a66b72a9 100644
--- a/lib/primitives/keyring.js
+++ b/lib/primitives/keyring.js
@@ -11,7 +11,6 @@ var assert = require('assert');
 var util = require('../utils/util');
 var encoding = require('../utils/encoding');
 var crypto = require('../crypto/crypto');
-var networks = require('../protocol/networks');
 var Network = require('../protocol/network');
 var BufferReader = require('../utils/reader');
 var StaticWriter = require('../utils/staticwriter');
@@ -124,7 +123,7 @@ KeyRing.prototype.refresh = function refresh() {
  * @private
  * @param {Buffer} key
  * @param {Boolean?} compressed
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  */
 
 KeyRing.prototype.fromPrivate = function fromPrivate(key, compressed, network) {
@@ -147,7 +146,7 @@ KeyRing.prototype.fromPrivate = function fromPrivate(key, compressed, network) {
  * Instantiate keyring from a private key.
  * @param {Buffer} key
  * @param {Boolean?} compressed
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  * @returns {KeyRing}
  */
 
@@ -159,7 +158,7 @@ KeyRing.fromPrivate = function fromPrivate(key, compressed, network) {
  * Inject data from public key.
  * @private
  * @param {Buffer} key
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  */
 
 KeyRing.prototype.fromPublic = function fromPublic(key, network) {
@@ -203,7 +202,7 @@ KeyRing.generate = function(compressed, network) {
 /**
  * Instantiate keyring from a public key.
  * @param {Buffer} publicKey
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  * @returns {KeyRing}
  */
 
@@ -215,7 +214,7 @@ KeyRing.fromPublic = function fromPublic(key, network) {
  * Inject data from public key.
  * @private
  * @param {Buffer} privateKey
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  */
 
 KeyRing.prototype.fromKey = function fromKey(key, compressed, network) {
@@ -235,7 +234,7 @@ KeyRing.prototype.fromKey = function fromKey(key, compressed, network) {
 /**
  * Instantiate keyring from a public key.
  * @param {Buffer} publicKey
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  * @returns {KeyRing}
  */
 
@@ -248,7 +247,7 @@ KeyRing.fromKey = function fromKey(key, compressed, network) {
  * @private
  * @param {Buffer} key
  * @param {Script} script
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  */
 
 KeyRing.prototype.fromScript = function fromScript(key, script, compressed, network) {
@@ -269,7 +268,7 @@ KeyRing.prototype.fromScript = function fromScript(key, script, compressed, netw
  * Instantiate keyring from script.
  * @param {Buffer} key
  * @param {Script} script
- * @param {(NetworkType|Network)} network
+ * @param {(NetworkType|Network)?} network
  * @returns {KeyRing}
  */
 
@@ -302,13 +301,18 @@ KeyRing.prototype.getSecretSize = function getSecretSize() {
  * @returns {Base58String}
  */
 
-KeyRing.prototype.toSecret = function toSecret() {
+KeyRing.prototype.toSecret = function toSecret(network) {
   var size = this.getSecretSize();
   var bw = new StaticWriter(size);
 
   assert(this.privateKey, 'Cannot serialize without private key.');
 
-  bw.writeU8(this.network.keyPrefix.privkey);
+  if (!network)
+    network = this.network;
+
+  network = Network.get(network);
+
+  bw.writeU8(network.keyPrefix.privkey);
   bw.writeBytes(this.privateKey);
 
   if (this.publicKey.length === 33)
@@ -323,23 +327,15 @@ KeyRing.prototype.toSecret = function toSecret() {
  * Inject properties from serialized CBitcoinSecret.
  * @private
  * @param {Base58String} secret
- * @param {Network?} network
+ * @param {(Network|NetworkType)?} network
  */
 
 KeyRing.prototype.fromSecret = function fromSecret(data, network) {
   var br = new BufferReader(base58.decode(data), true);
-  var i, prefix, version, type, key, compressed;
+  var version, key, compressed;
 
   version = br.readU8();
-
-  for (i = 0; i < networks.types.length; i++) {
-    type = networks.types[i];
-    prefix = networks[type].keyPrefix.privkey;
-    if (version === prefix)
-      break;
-  }
-
-  assert(i < networks.types.length, 'Network not found.');
+  network = Network.fromWIF(version, network);
 
   key = br.readBytes(32);
 
@@ -352,18 +348,13 @@ KeyRing.prototype.fromSecret = function fromSecret(data, network) {
 
   br.verifyChecksum();
 
-  this.fromPrivate(key, compressed, type);
-
-  if (network && !this.verifyNetwork(network))
-    throw new Error('Network mismatch for WIF.');
-
-  return this;
+  return this.fromPrivate(key, compressed, network);
 };
 
 /**
  * Instantiate a keyring from a serialized CBitcoinSecret.
  * @param {Base58String} secret
- * @param {Network?} network
+ * @param {(Network|NetworkType)?} network
  * @returns {KeyRing}
  */
 
@@ -371,17 +362,6 @@ KeyRing.fromSecret = function fromSecret(data, network) {
   return new KeyRing().fromSecret(data, network);
 };
 
-/**
- * Verify network.
- * @param {(NetworkType|Network)} network
- * @returns {Boolean}
- */
-
-KeyRing.prototype.verifyNetwork = function verifyNetwork(network) {
-  network = Network.get(network);
-  return this.network.keyPrefix.privkey === network.keyPrefix.privkey;
-};
-
 /**
  * Get private key.
  * @param {String?} enc - Can be `"hex"`, `"base58"`, or `null`.
diff --git a/lib/protocol/network.js b/lib/protocol/network.js
index c25beaf1..d4d35787 100644
--- a/lib/protocol/network.js
+++ b/lib/protocol/network.js
@@ -235,22 +235,121 @@ Network.ensure = function ensure(type) {
 };
 
 /**
- * Get a network by its magic number.
+ * Get a network by an associated comparator.
+ * @private
+ * @param {Object} value
+ * @param {Function} compare
+ * @param {Network|null} network
+ * @param {String} name
  * @returns {Network}
  */
 
-Network.fromMagic = function fromMagic(magic) {
+Network.by = function by(value, compare, network, name) {
   var i, type;
 
+  if (network) {
+    network = Network.get(network);
+    if (compare(network, value))
+      return network;
+    throw new Error('Network mismatch for ' + name + '.');
+  }
+
   for (i = 0; i < networks.types.length; i++) {
     type = networks.types[i];
-    if (magic === networks[type].magic)
-      break;
+    network = networks[type];
+    if (compare(network, value))
+      return Network.get(type);
   }
 
-  assert(i < networks.types.length, 'Network not found.');
+  throw new Error('Network not found for ' + name + '.');
+};
 
-  return Network.get(type);
+/**
+ * Get a network by its magic number.
+ * @param {Number} value
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromMagic = function fromMagic(value, network) {
+  return Network.by(value, cmpMagic, network, 'magic number');
+};
+
+/**
+ * Get a network by its WIF prefix.
+ * @param {Number} value
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromWIF = function fromWIF(prefix, network) {
+  return Network.by(prefix, cmpWIF, network, 'WIF');
+};
+
+/**
+ * Get a network by its xpubkey prefix.
+ * @param {Number} value
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromPublic = function fromPublic(prefix, network) {
+  return Network.by(prefix, cmpPub, network, 'xpubkey');
+};
+
+/**
+ * Get a network by its xprivkey prefix.
+ * @param {Number} value
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromPrivate = function fromPrivate(prefix, network) {
+  return Network.by(prefix, cmpPriv, network, 'xprivkey');
+};
+
+/**
+ * Get a network by its xpubkey base58 prefix.
+ * @param {String} prefix
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromPublic58 = function fromPublic58(prefix, network) {
+  return Network.by(prefix, cmpPub58, network, 'xpubkey');
+};
+
+/**
+ * Get a network by its xprivkey base58 prefix.
+ * @param {String} prefix
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromPrivate58 = function fromPrivate58(prefix, network) {
+  return Network.by(prefix, cmpPriv58, network, 'xprivkey');
+};
+
+/**
+ * Get a network by its base58 address prefix.
+ * @param {Number} value
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromAddress = function fromAddress(prefix, network) {
+  return Network.by(prefix, cmpAddress, network, 'base58 address');
+};
+
+/**
+ * Get a network by its bech32 address prefix.
+ * @param {String} hrp
+ * @param {Network?} network
+ * @returns {Network}
+ */
+
+Network.fromBech32 = function fromBech32(hrp, network) {
+  return Network.by(hrp, cmpBech32, network, 'bech32 address');
 };
 
 /**
@@ -302,6 +401,48 @@ function cmpNode(a, b) {
   return a.height - b.height;
 }
 
+function cmpMagic(network, magic) {
+  return network.magic === magic;
+}
+
+function cmpWIF(network, prefix) {
+  return network.keyPrefix.privkey === prefix;
+}
+
+function cmpPub(network, prefix) {
+  return network.keyPrefix.xpubkey === prefix;
+}
+
+function cmpPriv(network, prefix) {
+  return network.keyPrefix.xprivkey === prefix;
+}
+
+function cmpPub58(network, prefix) {
+  return network.keyPrefix.xpubkey58 === prefix;
+}
+
+function cmpPriv58(network, prefix) {
+  return network.keyPrefix.xprivkey58 === prefix;
+}
+
+function cmpAddress(network, prefix) {
+  var prefixes = network.addressPrefix;
+
+  switch (prefix) {
+    case prefixes.pubkeyhash:
+    case prefixes.scripthash:
+    case prefixes.witnesspubkeyhash:
+    case prefixes.witnessscripthash:
+      return true;
+  }
+
+  return false;
+}
+
+function cmpBech32(network, hrp) {
+  return network.addressPrefix.bech32 === hrp;
+}
+
 /*
  * Expose
  */