diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index fc812373..d04b66e2 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -498,14 +498,8 @@ Chain.prototype._verify = function _verify(block, prev, callback) {
     return callback(new VerifyError(block, 'invalid', ret.reason, ret.score));
 
   // Skip the genesis block. Skip all blocks in spv mode.
-  if (this.options.spv || this.isGenesis(block)) {
-    return callback(null, {
-      flags: constants.flags.MANDATORY_VERIFY_FLAGS,
-      lockFlags: constants.flags.MANDATORY_LOCKTIME_FLAGS,
-      segwit: false,
-      csv: false
-    });
-  }
+  if (this.options.spv || this.isGenesis(block))
+    return callback(null, new DeploymentState());
 
   // Ensure it's not an orphan
   if (!prev) {
@@ -542,15 +536,15 @@ Chain.prototype._verify = function _verify(block, prev, callback) {
         return callback(err);
 
       // Expose the state of csv and segwit globally.
-      self.csvActive = state.csv;
-      self.segwitActive = state.segwit;
+      self.csvActive = state.hasCSV();
+      self.segwitActive = state.hasWitness();
 
       // Can't verify any further when merkleblock or headers.
       if (self.options.spv)
         return callback(null, state);
 
       // Make sure the height contained in the coinbase is correct.
-      if (state.coinbaseHeight) {
+      if (state.hasBIP34()) {
         if (block.getCoinbaseHeight() !== height) {
           return callback(new VerifyError(block,
             'invalid',
@@ -560,7 +554,7 @@ Chain.prototype._verify = function _verify(block, prev, callback) {
       }
 
       // Check the commitment hash for segwit.
-      if (state.segwit) {
+      if (state.hasWitness()) {
         commitmentHash = block.commitmentHash;
         if (commitmentHash) {
           if (!block.witnessNonce) {
@@ -635,13 +629,7 @@ Chain.prototype._verify = function _verify(block, prev, callback) {
 Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ancestors, callback) {
   var self = this;
   var height = prev.height + 1;
-  var state = {
-    flags: constants.flags.MANDATORY_VERIFY_FLAGS,
-    lockFlags: constants.flags.MANDATORY_LOCKTIME_FLAGS,
-    coinbaseHeight: false,
-    segwit: false,
-    csv: false
-  };
+  var state = new DeploymentState();
 
   // For some reason bitcoind has p2sh in the
   // mandatory flags by default, when in reality
@@ -651,8 +639,8 @@ Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ance
   // not have a signature. See:
   // 6a26d2ecb67f27d1fa5524763b49029d7106e91e3cc05743073461a719776192
   // 9c08a4d78931342b37fd5f72900fb9983087e6f46c4a097d8a1f52c74e28eaf6
-  if (block.ts < constants.block.BIP16_TIME)
-    state.flags &= ~constants.flags.VERIFY_P2SH;
+  if (block.ts >= constants.block.BIP16_TIME)
+    state.flags |= constants.flags.VERIFY_P2SH;
 
   // Only allow version 2 blocks (coinbase height)
   // once the majority of blocks are using it.
@@ -678,7 +666,7 @@ Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ance
 
   // Make sure the height contained in the coinbase is correct.
   if (block.version >= 2 && prev.isUpgraded(2, ancestors))
-    state.coinbaseHeight = true;
+    state.bip34 = true;
 
   // Signature validation is now enforced (bip66)
   if (block.version >= 3 && prev.isUpgraded(3, ancestors))
@@ -690,10 +678,8 @@ Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ance
 
   // Segregrated witness is now usable (bip141 - segnet3)
   if (this.network.segwitHeight !== -1 && height >= this.network.segwitHeight) {
-    if (block.version >= 5 && prev.isUpgraded(5, ancestors)) {
+    if (block.version >= 5 && prev.isUpgraded(5, ancestors))
       state.flags |= constants.flags.VERIFY_WITNESS;
-      state.segwit = true;
-    }
   }
 
   utils.serial([
@@ -708,7 +694,6 @@ Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ance
           state.flags |= constants.flags.VERIFY_CHECKSEQUENCEVERIFY;
           state.lockFlags |= constants.flags.VERIFY_SEQUENCE;
           state.lockFlags |= constants.flags.MEDIAN_TIME_PAST;
-          state.csv = true;
         }
 
         return next();
@@ -720,10 +705,8 @@ Chain.prototype._checkDeployments = function _checkDeployments(block, prev, ance
         if (err)
           return next(err);
 
-        if (active) {
+        if (active)
           state.flags |= constants.flags.VERIFY_WITNESS;
-          state.segwit = true;
-        }
 
         return next();
       });
@@ -2366,8 +2349,8 @@ Chain.prototype._getInitialState = function _getInitialState(callback) {
         if (err)
           return callback(err);
 
-        self.csvActive = state.csv;
-        self.segwitActive = state.segwit;
+        self.csvActive = state.hasCSV();
+        self.segwitActive = state.hasWitness();
 
         return callback();
       });
@@ -2509,6 +2492,78 @@ Chain.prototype.checkLocks = function checkLocks(prev, tx, flags, callback) {
   });
 };
 
+/**
+ * Represents the deployment state of the chain.
+ * @constructor
+ * @property {VerifyFlags} flags
+ * @property {LockFlags} lockFlags
+ * @property {Boolean} bip34
+ */
+
+function DeploymentState() {
+  if (!(this instanceof DeploymentState))
+    return new DeploymentState();
+
+  this.flags = constants.flags.MANDATORY_VERIFY_FLAGS;
+  this.flags &= ~constants.flags.VERIFY_P2SH;
+  this.lockFlags = constants.flags.MANDATORY_LOCKTIME_FLAGS;
+  this.bip34 = false;
+}
+
+/**
+ * Test whether p2sh is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasP2SH = function hasP2SH() {
+  return (this.flags & constants.flags.VERIFY_P2SH) !== 0;
+};
+
+/**
+ * Test whether bip34 (coinbase height) is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasBIP34 = function hasBIP34() {
+  return this.bip34;
+};
+
+/**
+ * Test whether bip66 (VERIFY_DERSIG) is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasBIP66 = function hasBIP66() {
+  return (this.flags & constants.flags.VERIFY_DERSIG) !== 0;
+};
+
+/**
+ * Test whether cltv is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasCLTV = function hasCLTV() {
+  return (this.flags & constants.flags.VERIFY_CHECKLOCKTIMEVERIFY) !== 0;
+};
+
+/**
+ * Test whether csv is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasCSV = function hasCSV() {
+  return (this.flags & constants.flags.VERIFY_CHECKSEQUENCEVERIFY) !== 0;
+};
+
+/**
+ * Test whether segwit is active.
+ * @returns {Boolean}
+ */
+
+DeploymentState.prototype.hasWitness = function hasWitness() {
+  return (this.flags & constants.flags.VERIFY_WITNESS) !== 0;
+};
+
 /*
  * Expose
  */
diff --git a/lib/bcoin/wallet.js b/lib/bcoin/wallet.js
index a0691ffc..c94b9d09 100644
--- a/lib/bcoin/wallet.js
+++ b/lib/bcoin/wallet.js
@@ -2719,9 +2719,13 @@ MasterKey.prototype.toJSON = function toJSON() {
  */
 
 MasterKey.prototype.fromJSON = function fromJSON(json) {
+  assert(typeof json.encrypted === 'boolean');
+
   this.encrypted = json.encrypted;
 
   if (json.encrypted) {
+    assert(typeof json.iv === 'string');
+    assert(typeof json.ciphertext === 'string');
     this.iv = new Buffer(json.iv, 'hex');
     this.ciphertext = new Buffer(json.ciphertext, 'hex');
   } else {