diff --git a/BIP32.js b/BIP32.js
index 3e1705f..f333b41 100644
--- a/BIP32.js
+++ b/BIP32.js
@@ -290,8 +290,7 @@ BIP32.prototype.derive_child = function(i) {
     var il = new BigInteger(hash.slice(0, 64), 16);
     var ir = Crypto.util.hexToBytes(hash.slice(64, 128));
     */
-    var hmac = crypto.createHmac('sha512', this.chain_code);
-    var hash = hmac.update(data).digest();
+    var hash = coinUtil.sha512hmac(data, this.chain_code);
     var il = bignum.fromBuffer(hash.slice(0, 32), {size: 32});
     var ir = hash.slice(32, 64);
 
@@ -317,8 +316,7 @@ BIP32.prototype.derive_child = function(i) {
     var ir = Crypto.util.hexToBytes(hash.slice(64, 128));
     */
     var data = Buffer.concat([this.eckey.public, ib]);
-    var hmac = crypto.createHmac('sha512', this.chain_code);
-    var hash = hmac.update(data).digest();
+    var hash = coinUtil.sha512hmac(data, this.chain_code);
     var il = bignum.fromBuffer(hash.slice(0, 32), {size: 32});
     var ir = hash.slice(32, 64);
 
diff --git a/browser/build.js b/browser/build.js
index 736ae3d..24efa9b 100644
--- a/browser/build.js
+++ b/browser/build.js
@@ -24,6 +24,7 @@ var pack = function (params) {
 
 var modules = [
   'Address',
+  'BIP32',
   'Block',
   'Bloom',
   'Buffers.monkey',
diff --git a/package.json b/package.json
index eb5a3c5..61d4857 100644
--- a/package.json
+++ b/package.json
@@ -47,6 +47,7 @@
     "postinstall": "node browser/build.js -a"
   },
   "dependencies": {
+    "jssha": "=1.5.0",
     "soop": "=0.1.5",
     "base58-native": "=0.1.3",
     "bindings": "=1.1.1",
diff --git a/test/index.html b/test/index.html
index bbd0d61..510190e 100644
--- a/test/index.html
+++ b/test/index.html
@@ -17,6 +17,7 @@
 
     <script src="test.Address.js"></script>
     <script src="test.basic.js"></script>
+    <script src="test.BIP32.js"></script>
     <script src="test.Block.js"></script>
     <script src="test.Bloom.js"></script>
     <script src="test.Connection.js"></script>
diff --git a/util/util.js b/util/util.js
index 921cda5..dc7972b 100644
--- a/util/util.js
+++ b/util/util.js
@@ -3,6 +3,7 @@ var bignum = require('bignum');
 var Binary = require('binary');
 var Put = require('bufferput');
 var buffertools = require('buffertools');
+var jssha = require('jssha');
 var browser;
 var inBrowser = !process.versions;
 if (inBrowser) {
@@ -13,7 +14,20 @@ if (inBrowser) {
 var sha256 = exports.sha256 = function(data) {
   return new Buffer(crypto.createHash('sha256').update(data).digest('binary'), 'binary');
 };
-var ripe160 = exports.ripe160 = function(data) {
+
+var sha512hmac = exports.sha512hmac = function (data, key) {
+  if (inBrowser) {
+    var j = new jssha(data.toString('hex'), 'HEX');
+    var hash = j.getHMAC(key.toString('hex'), "HEX", "SHA-512", "HEX");
+    hash = new Buffer(hash, 'hex');
+    return hash;
+  };
+  var hmac = crypto.createHmac('sha512', key);
+  var hash = hmac.update(data).digest();
+  return hash;
+};
+
+var ripe160 = exports.ripe160 = function (data) {
   if (!Buffer.isBuffer(data)) {
     throw new Error('arg should be a buffer');
   }