diff --git a/CHANGELOG.md b/CHANGELOG.md
index b063996..a17a983 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 ------------------
 - bugfix: if private key was less than 32 bytes, pad out to 32 bytes with leading zeros (this happens in derive)
 - changed behavior of `privateExtendedKey()` and `publicExtendedKey()` to return base 58 encoded `string` instead of `Buffer`
+- changed behavior of `fromExtendedKey()` from accepting a type of `Buffer` bytes to base58 `string`
 
 0.2.0 / 2014-06-25
 ------------------
diff --git a/lib/hdkey.js b/lib/hdkey.js
index 7c25171..eed1082 100644
--- a/lib/hdkey.js
+++ b/lib/hdkey.js
@@ -175,11 +175,13 @@ HDKey.fromMasterSeed = function(seedBuffer, versions) {
   return hdkey
 }
 
-HDKey.fromExtendedKey = function(keyBuffer, versions) {
+HDKey.fromExtendedKey = function(base58key, versions) {
   // => version(4) || depth(1) || fingerprint(4) || index(4) || chain(32) || key(33)
   versions = versions || BITCOIN_VERSIONS
   var hdkey = new HDKey(versions)
 
+  var keyBuffer = cs.decode(base58key)
+
   var version = keyBuffer.readUInt32BE(0)
   assert(version === versions.private || version === versions.public, 'Version mismatch: does not match private or public')
 
diff --git a/test/hdkey.test.js b/test/hdkey.test.js
index 34caa3e..05d93c6 100644
--- a/test/hdkey.test.js
+++ b/test/hdkey.test.js
@@ -62,8 +62,7 @@ describe('hdkey', function() {
       it('should parse it', function() {
         //m/0/2147483647'/1/2147483646'/2
         var key = "xprvA2nrNbFZABcdryreWet9Ea4LvTJcGsqrMzxHx98MMrotbir7yrKCEXw7nadnHM8Dq38EGfSh6dqA9QWTyefMLEcBYJUuekgW4BYPJcr9E7j"
-        var keyBuffer = cs.decode(key)
-        var hdkey = HDKey.fromExtendedKey(keyBuffer)
+        var hdkey = HDKey.fromExtendedKey(key)
         assert.equal(hdkey.versions.private, 0x0488ade4)
         assert.equal(hdkey.versions.public, 0x0488b21e)
         assert.equal(hdkey.depth, 5)
@@ -80,8 +79,7 @@ describe('hdkey', function() {
       it('should parse it', function() {
         //m/0/2147483647'/1/2147483646'/2
         var key = "xpub6FnCn6nSzZAw5Tw7cgR9bi15UV96gLZhjDstkXXxvCLsUXBGXPdSnLFbdpq8p9HmGsApME5hQTZ3emM2rnY5agb9rXpVGyy3bdW6EEgAtqt"
-        var keyBuffer = cs.decode(key)
-        var hdkey = HDKey.fromExtendedKey(keyBuffer)
+        var hdkey = HDKey.fromExtendedKey(key)
         assert.equal(hdkey.versions.private, 0x0488ade4)
         assert.equal(hdkey.versions.public, 0x0488b21e)
         assert.equal(hdkey.depth, 5)
@@ -98,8 +96,7 @@ describe('hdkey', function() {
   describe('> when deriving public key', function() {
     it('should work', function() {
       var key = "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8"
-      var keyBuffer = cs.decode(key)
-      var hdkey = HDKey.fromExtendedKey(keyBuffer)
+      var hdkey = HDKey.fromExtendedKey(key)
 
       var path = "m/3353535/2223/0/99424/4/33"
       var derivedHDKey = hdkey.derive(path)