diff --git a/lib/bcoin/hd.js b/lib/bcoin/hd.js
index c645c1bd..5449d949 100644
--- a/lib/bcoin/hd.js
+++ b/lib/bcoin/hd.js
@@ -160,7 +160,7 @@ function HDPrivateKey(options) {
 
   this._build(data);
 
-  if (new bn(data.parentFingerPrint).cmpn(0) === 0)
+  if (utils.readU32BE(data.parentFingerPrint) === 0)
     this.isMaster = true;
   else
     this.isMaster = false;
@@ -203,7 +203,7 @@ HDPrivateKey.prototype.scan44 = function scan44(options, txByAddress, callback)
         : root.derive(accountIndex, true);
 
       if (isAccount)
-        accountIndex = new bn(self.childIndex).toNumber() - constants.hd.hardened;
+        accountIndex = utils.readU32BE(self.childIndex) - constants.hd.hardened;
 
       // 2. derive the external chain node of this account
       var chain = account.derive(chainConstant);
@@ -462,15 +462,15 @@ HDPrivateKey.prototype.deriveCosignerAddress = function deriveCosignerAddress(co
 };
 
 HDPrivateKey.prototype.isPurpose45 = function isPurpose45(options) {
-  if (new bn(this.depth).toNumber() !== 1)
+  if (utils.readU8(this.depth) !== 1)
     return false;
-  return new bn(this.childIndex).toNumber() === constants.hd.hardened + 45;
+  return utils.readU32BE(this.childIndex) === constants.hd.hardened + 45;
 };
 
 HDPrivateKey.prototype.isAccount44 = function isAccount44(options) {
-  if (new bn(this.childIndex).toNumber() < constants.hd.hardened)
+  if (utils.readU32BE(this.childIndex) < constants.hd.hardened)
     return false;
-  return new bn(this.depth).toNumber() === 3;
+  return utils.readU8(this.depth) === 3;
 };
 
 HDPrivateKey.getPath = function getPath(options) {
@@ -516,57 +516,31 @@ HDPrivateKey.prototype._normalize = function _normalize(data) {
   }
 
   // version = uint_32be
-  if (typeof data.version === 'string')
-    data.version = new Buffer(data.version, 'hex');
-  else if (typeof data.version === 'number')
+  if (typeof data.version === 'number')
     data.version = array32(data.version);
 
   // depth = unsigned char
-  if (typeof data.depth === 'string')
-    data.depth = new Buffer(data.depth, 'hex');
-  else if (typeof data.depth === 'number')
+  if (typeof data.depth === 'number')
     data.depth = new Buffer([data.depth]);
 
-  if (new bn(data.depth).toNumber() > 0xff)
+  if (utils.readU8(data.depth) > 0xff)
     throw new Error('Depth is too high');
 
   // parent finger print = uint_32be
-  if (typeof data.parentFingerPrint === 'string')
-    data.parentFingerPrint = new Buffer(data.parentFingerPrint, 'hex');
-  else if (typeof data.parentFingerPrint === 'number')
+  if (typeof data.parentFingerPrint === 'number')
     data.parentFingerPrint = array32(data.parentFingerPrint);
 
   // child index = uint_32be
-  if (typeof data.childIndex === 'string')
-    data.childIndex = new Buffer(data.childIndex, 'hex');
-  else if (typeof data.childIndex === 'number')
+  if (typeof data.childIndex === 'number')
     data.childIndex = array32(data.childIndex);
 
   // chain code = 32 bytes
   if (typeof data.chainCode === 'string')
     data.chainCode = new Buffer(data.chainCode, 'hex');
 
-  // private key = 32 bytes
-  if (data.privateKey) {
-    if (data.privateKey.getPrivateKey)
-      data.privateKey = data.privateKey.getPrivateKey();
-    else if (typeof data.privateKey === 'string')
-      data.privateKey = utils.ensureBuffer(data.privateKey);
-  }
-
-  // public key = 33 bytes
-  if (data.publicKey) {
-    if (data.publicKey.getPublicKey)
-      data.publicKey = data.privateKey.getPublicKey();
-    else if (typeof data.publicKey === 'string')
-      data.publicKey = utils.ensureBuffer(data.publicKey);
-  }
-
   // checksum = 4 bytes
   if (typeof data.checksum === 'string')
     data.checksum = new Buffer(data.checksum, 'hex');
-  else if (typeof data.checksum === 'number')
-    data.checksum = array32(data.checksum);
 
   return data;
 };
@@ -589,9 +563,9 @@ HDPrivateKey.prototype._seed = function _seed(seed) {
 
   return {
     version: network[this.network].prefixes.xprivkey,
-    depth: 0,
-    parentFingerPrint: 0,
-    childIndex: 0,
+    depth: new Buffer([0]),
+    parentFingerPrint: new Buffer([0, 0, 0, 0]),
+    childIndex: new Buffer([0, 0, 0, 0]),
     chainCode: hash.slice(32, 64),
     privateKey: hash.slice(0, 32),
     checksum: null
@@ -612,9 +586,9 @@ HDPrivateKey._generate = function _generate(privateKey, entropy) {
 
   return {
     version: null,
-    depth: 0,
-    parentFingerPrint: 0,
-    childIndex: 0,
+    depth: new Buffer([0]),
+    parentFingerPrint: new Buffer([0, 0, 0, 0]),
+    childIndex: new Buffer([0, 0, 0, 0]),
     chainCode: entropy,
     privateKey: privateKey,
     checksum: null
@@ -761,7 +735,7 @@ HDPrivateKey.prototype.derive = function derive(index, hardened) {
     network: this.network,
     data: {
       version: this.version,
-      depth: new bn(this.depth).toNumber() + 1,
+      depth: utils.readU8(this.depth) + 1,
       parentFingerPrint: this.fingerPrint,
       childIndex: index,
       chainCode: chainCode,
@@ -964,7 +938,7 @@ function HDPublicKey(options) {
 
   this._build(data);
 
-  if (new bn(data.parentFingerPrint).cmpn(0) === 0)
+  if (utils.readU32BE(data.parentFingerPrint) === 0)
     this.isMaster = true;
   else
     this.isMaster = false;
@@ -1118,7 +1092,7 @@ HDPublicKey.prototype.derive = function derive(index, hardened) {
     network: this.network,
     data: {
       version: this.version,
-      depth: new bn(this.depth).toNumber() + 1,
+      depth: utils.readU8(this.depth) + 1,
       parentFingerPrint: this.fingerPrint,
       childIndex: index,
       chainCode: chainCode,