diff --git a/lib/bcoin/hd.js b/lib/bcoin/hd.js
index 622f5cda..72ea8b28 100644
--- a/lib/bcoin/hd.js
+++ b/lib/bcoin/hd.js
@@ -455,7 +455,7 @@ HDPrivateKey.prototype.derive = function derive(index, hardened) {
 
   data = p.render();
 
-  hash = utils.sha512hmac(data, this.chainCode);
+  hash = utils.hmac('sha512', data, this.chainCode);
   leftPart = new bn(hash.slice(0, 32));
   chainCode = hash.slice(32, 64);
 
@@ -699,7 +699,7 @@ HDPrivateKey.parseSeed = function parseSeed(seed, networkType) {
     throw new Error('Entropy not in range.');
   }
 
-  hash = utils.sha512hmac(data, 'Bitcoin seed');
+  hash = utils.hmac('sha512', data, 'Bitcoin seed');
 
   return {
     version: networkType
@@ -1045,7 +1045,7 @@ HDPublicKey.prototype.derive = function derive(index, hardened) {
   p.writeU32BE(index);
   data = p.render();
 
-  hash = utils.sha512hmac(data, this.chainCode);
+  hash = utils.hmac('sha512', data, this.chainCode);
   leftPart = new bn(hash.slice(0, 32));
   chainCode = hash.slice(32, 64);
 
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index bc16edcd..0c2e9bf3 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -197,6 +197,21 @@ utils.isBase58 = function isBase58(msg) {
   return typeof msg === 'string' && /^[1-9a-zA-Z]+$/.test(msg);
 };
 
+/**
+ * Hash with chosen algorithm.
+ * @param {String} alg
+ * @param {Buffer|String} data
+ * @param {String?} enc - Any buffer-supported encoding.
+ * @returns {Buffer}
+ */
+
+utils.hash = function _hash(alg, data, enc) {
+  if (!crypto)
+    return new Buffer(hash[alg]().update(data, enc).digest());
+
+  return crypto.createHash(alg).update(data, enc).digest();
+};
+
 /**
  * Hash with ripemd160.
  * @param {Buffer|String} data
@@ -205,10 +220,7 @@ utils.isBase58 = function isBase58(msg) {
  */
 
 utils.ripemd160 = function ripemd160(data, enc) {
-  if (!crypto)
-    return new Buffer(hash.ripemd160().update(data, enc).digest());
-
-  return crypto.createHash('ripemd160').update(data, enc).digest();
+  return utils.hash('ripemd160', data, enc);
 };
 
 /**
@@ -219,10 +231,18 @@ utils.ripemd160 = function ripemd160(data, enc) {
  */
 
 utils.sha1 = function sha1(data, enc) {
-  if (!crypto)
-    return new Buffer(hash.sha1().update(data, enc).digest());
+  return utils.hash('sha1', data, enc);
+};
 
-  return crypto.createHash('sha1').update(data, enc).digest();
+/**
+ * Hash with sha256.
+ * @param {Buffer|String} data
+ * @param {String?} enc - Any buffer-supported encoding.
+ * @returns {Buffer}
+ */
+
+utils.sha256 = function sha256(data, enc) {
+  return utils.hash('sha256', data, enc);
 };
 
 /**
@@ -236,31 +256,6 @@ utils.ripesha = function ripesha(data, enc) {
   return utils.ripemd160(utils.sha256(data, enc));
 };
 
-/**
- * Create a sha256 checksum (common in bitcoin).
- * @param {Buffer|String} data
- * @param {String?} enc - Any buffer-supported encoding.
- * @returns {Buffer}
- */
-
-utils.checksum = function checksum(data, enc) {
-  return utils.dsha256(data, enc).slice(0, 4);
-};
-
-/**
- * Hash with sha256.
- * @param {Buffer|String} data
- * @param {String?} enc - Any buffer-supported encoding.
- * @returns {Buffer}
- */
-
-utils.sha256 = function sha256(data, enc) {
-  if (!crypto)
-    return new Buffer(hash.sha256().update(data, enc).digest());
-
-  return crypto.createHash('sha256').update(data, enc).digest();
-};
-
 /**
  * Hash with sha256 twice (OP_HASH256).
  * @param {Buffer|String} data
@@ -273,24 +268,34 @@ utils.dsha256 = function dsha256(data, enc) {
 };
 
 /**
- * Create a sha512 HMAC.
+ * Create a sha256 checksum (common in bitcoin).
+ * @param {Buffer|String} data
+ * @param {String?} enc - Any buffer-supported encoding.
+ * @returns {Buffer}
+ */
+
+utils.checksum = function checksum(data, enc) {
+  return utils.dsha256(data, enc).slice(0, 4);
+};
+
+/**
+ * Create an HMAC.
+ * @param {String} alg
  * @param {Buffer} data
  * @param {Buffer} salt
  * @returns {Buffer} HMAC
  */
 
-utils.sha512hmac = function sha512hmac(data, salt) {
-  var hmac, result;
+utils.hmac = function hmac(alg, data, salt) {
+  var hmac;
 
   if (!crypto) {
-    hmac = hash.hmac(hash.sha512, salt);
+    hmac = hash.hmac(hash[alg], salt);
     return new Buffer(hmac.update(data).digest());
   }
 
-  hmac = crypto.createHmac('sha512', salt);
-  result = hmac.update(data).digest();
-
-  return result;
+  hmac = crypto.createHmac(alg, salt);
+  return hmac.update(data).digest();
 };
 
 /**
@@ -299,6 +304,7 @@ utils.sha512hmac = function sha512hmac(data, salt) {
  * @param {Buffer} salt
  * @param {Number} iterations
  * @param {Number} dkLen - Output size.
+ * @param {String?} alg
  */
 
 /*!
@@ -308,9 +314,8 @@ utils.sha512hmac = function sha512hmac(data, salt) {
  * Copyright (c) 2014, JP Richardson
  */
 
-utils.pbkdf2 = function pbkdf2(key, salt, iterations, dkLen) {
-  var hLen = 64;
-  var DK, U, T, block1, l, r;
+utils.pbkdf2 = function pbkdf2(key, salt, iterations, dkLen, alg) {
+  var hLen, DK, U, T, block, l, r;
   var i, j, k, destPos, len;
 
   if (typeof key === 'string')
@@ -319,33 +324,44 @@ utils.pbkdf2 = function pbkdf2(key, salt, iterations, dkLen) {
   if (typeof salt === 'string')
     salt = new Buffer(salt, 'utf8');
 
+  if (!alg)
+    alg = 'sha512';
+
   if (crypto && crypto.pbkdf2Sync)
-    return crypto.pbkdf2Sync(key, salt, iterations, dkLen, 'sha512');
+    return crypto.pbkdf2Sync(key, salt, iterations, dkLen, alg);
+
+  if (alg === 'sha512')
+    hLen = 64;
+  else if (alg === 'sha256')
+    hLen = 32;
+  else if (alg === 'sha1' || alg === 'ripemd160')
+    hLen = 20;
+  else if (alg === 'md5')
+    hLen = 16;
 
   assert(dkLen <= 0xffffffff * hLen, 'Requested key length too long');
 
   DK = new Buffer(dkLen);
-  U = new Buffer(hLen);
   T = new Buffer(hLen);
-  block1 = new Buffer(salt.length + 4);
+  block = new Buffer(salt.length + 4);
 
   l = Math.ceil(dkLen / hLen);
   r = dkLen - (l - 1) * hLen;
 
-  salt.copy(block1, 0, 0, salt.length);
+  salt.copy(block, 0, 0, salt.length);
 
   for (i = 1; i <= l; i++) {
-    block1[salt.length + 0] = i >> 24 & 0xff;
-    block1[salt.length + 1] = i >> 16 & 0xff;
-    block1[salt.length + 2] = i >> 8 & 0xff;
-    block1[salt.length + 3] = i >> 0 & 0xff;
+    block[salt.length + 0] = (i >>> 24) & 0xff;
+    block[salt.length + 1] = (i >>> 16) & 0xff;
+    block[salt.length + 2] = (i >>> 8) & 0xff;
+    block[salt.length + 3] = (i >>> 0) & 0xff;
 
-    U = utils.sha512hmac(block1, key);
+    U = utils.hmac(alg, block, key);
 
     U.copy(T, 0, 0, hLen);
 
     for (j = 1; j < iterations; j++) {
-      U = utils.sha512hmac(U, key);
+      U = utils.hmac(alg, U, key);
 
       for (k = 0; k < hLen; k++)
         T[k] ^= U[k];
@@ -428,16 +444,17 @@ utils.decrypt = function decrypt(data, passphrase) {
  * @param {Buffer|String} passphrase
  * @param {(Buffer|String)?} salt
  * @param {Number} iterations
- * @param {Number} keySize - Key size in bits.
- * @param {Number} ivSize - IV size in bytes.
+ * @param {Number} dkLen
+ * @param {Number} ivLen
+ * @param {String?} alg
  * @returns {Buffer}
  */
 
-utils.pbkdf2key = function pbkdf2key(passphrase, salt, iterations, keySize, ivSize) {
-  var key = utils.pbkdf2(passphrase, salt || '', iterations, keySize + ivSize);
+utils.pbkdf2key = function pbkdf2key(passphrase, salt, iterations, dkLen, ivLen, alg) {
+  var key = utils.pbkdf2(passphrase, salt || '', iterations, dkLen + ivLen, alg);
   return {
-    key: key.slice(0, keySize),
-    iv: key.slice(keySize)
+    key: key.slice(0, dkLen),
+    iv: key.slice(dkLen)
   };
 };