diff --git a/lib/bcoin/address.js b/lib/bcoin/address.js
index b40c5ccf..b40d4ac9 100644
--- a/lib/bcoin/address.js
+++ b/lib/bcoin/address.js
@@ -161,17 +161,17 @@ Address.prototype.inspect = function inspect() {
 /**
  * Inject properties from base58 address.
  * @private
- * @param {Base58Address} address
+ * @param {Base58Address} data
  * @throws Parse error
  */
 
-Address.prototype.fromBase58 = function fromBase58(address) {
-  var i, prefix, type, version, nversion, hash, network, p;
+Address.prototype.fromBase58 = function fromBase58(data) {
+  var i, prefix, type, version, hash, network, p;
 
-  if (typeof address === 'string')
-    address = utils.fromBase58(address);
+  if (typeof data === 'string')
+    data = utils.fromBase58(data);
 
-  p = new BufferReader(address, true);
+  p = new BufferReader(data, true);
   prefix = p.readU8();
 
   for (i = 0; i < networks.types.length; i++) {
@@ -183,20 +183,17 @@ Address.prototype.fromBase58 = function fromBase58(address) {
 
   assert(type != null, 'Unknown address prefix.');
 
-  nversion = network.address.versions[type];
-
-  if (nversion == null)
-    nversion = -1;
-
-  if (nversion !== -1) {
+  if (data.length > 25) {
     version = p.readU8();
+    assert(data.length === 27 || data.length === 39);
     assert(version >= 0 && version <= 16, 'Bad program version.');
     assert(p.readU8() === 0, 'Address version padding is non-zero.');
   } else {
     version = -1;
+    assert(data.length === 25);
   }
 
-  if (type === 'witnessscripthash')
+  if (data.length === 39)
     hash = p.readBytes(32);
   else
     hash = p.readBytes(20);
@@ -233,6 +230,7 @@ Address.prototype.fromScript = function fromScript(script) {
 
   if (script.isProgram()) {
     program = script.toProgram();
+    // TODO: MAST support
     if (program.isUnknown())
       return;
     this.hash = program.data;
@@ -377,7 +375,7 @@ Address.fromScript = function fromScript(script) {
  */
 
 Address.prototype.fromHash = function fromHash(hash, type, version, network) {
-  var prefix, nversion;
+  var prefix;
 
   if (typeof hash === 'string')
     hash = new Buffer(hash, 'hex');
@@ -390,10 +388,6 @@ Address.prototype.fromHash = function fromHash(hash, type, version, network) {
 
   network = bcoin.network.get(network);
   prefix = network.address.prefixes[type];
-  nversion = network.address.versions[type];
-
-  if (version === -1 && nversion != null)
-    version = nversion;
 
   assert(prefix != null, 'Not a valid address prefix.');
 
@@ -403,6 +397,8 @@ Address.prototype.fromHash = function fromHash(hash, type, version, network) {
     assert(hash.length === 20, 'Hash is the wrong size.');
   else if (version === 0 && type === 'witnessscripthash')
     assert(hash.length === 32, 'Hash is the wrong size.');
+  else if (version === 1 && type === 'witnessscripthash')
+    assert(hash.length === 32, 'Hash is the wrong size.');
 
   this.hash = hash;
   this.type = type;
@@ -434,11 +430,15 @@ Address.fromHash = function fromHash(hash, type, version, network) {
  */
 
 Address.prototype.fromData = function fromData(data, type, version, network) {
-  if (type === 'witnessscripthash')
+  if (type === 'witnessscripthash') {
+    assert(version === 0);
     data = utils.sha256(data);
-  else
+  } else if (type === 'witnesspubkeyhash') {
+    assert(version === 0);
     data = utils.hash160(data);
-
+  } else {
+    data = utils.hash160(data);
+  }
   return this.fromHash(data, type, version, network);
 };
 
diff --git a/lib/bcoin/network.js b/lib/bcoin/network.js
index c4c92f01..a8f32877 100644
--- a/lib/bcoin/network.js
+++ b/lib/bcoin/network.js
@@ -137,7 +137,7 @@ Network.prototype.getRate = function getRate() {
  */
 
 Network.create = function create(options) {
-  var net;
+  var network;
 
   if (typeof options === 'string')
     options = networks[options];
@@ -147,14 +147,14 @@ Network.create = function create(options) {
   if (Network[options.type])
     return Network[options.type];
 
-  net = new Network(options);
+  network = new Network(options);
 
-  Network[net.type] = net;
+  Network[network.type] = network;
 
   if (!Network.primary)
-    Network.primary = net;
+    Network.primary = network;
 
-  return net;
+  return network;
 };
 
 /**
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index f6144347..6cd95e58 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -2911,7 +2911,8 @@ Script.prototype.toProgram = function toProgram() {
 };
 
 /**
- * Test whether the output script is a pay-to-witness-pubkeyhash script.
+ * Test whether the output script is
+ * a pay-to-witness-pubkeyhash program.
  * @returns {Boolean}
  */
 
@@ -2922,7 +2923,8 @@ Script.prototype.isWitnessPubkeyhash = function isWitnessPubkeyhash() {
 };
 
 /**
- * Test whether the output script is a pay-to-witness-scripthash script.
+ * Test whether the output script is
+ * a pay-to-witness-scripthash program.
  * @returns {Boolean}
  */
 
@@ -2932,6 +2934,18 @@ Script.prototype.isWitnessScripthash = function isWitnessScripthash() {
     && this.raw[1] === 0x20;
 };
 
+/**
+ * Test whether the output script
+ * is a pay-to-mast program.
+ * @returns {Boolean}
+ */
+
+Script.prototype.isMAST = function isMAST() {
+  return this.raw.length === 34
+    && this.raw[0] === opcodes.OP_1
+    && this.raw[1] === 0x20;
+};
+
 /**
  * Test whether the output script is unspendable.
  * @returns {Boolean}
@@ -4622,6 +4636,7 @@ function Program(version, data) {
   this.data = data;
   this.type = null;
 
+  // TODO: MAST support
   if (version > 0) {
     // No interpretation of script (anyone can spend)
     this.type = 'unknown';