--- a/lib/openid-php/Auth/OpenID/DiffieHellman.php
+++ b/lib/openid-php/Auth/OpenID/DiffieHellman.php
@@ -1,1 +1,114 @@
+<?php
 
+/**
+ * The OpenID library's Diffie-Hellman implementation.
+ *
+ * PHP versions 4 and 5
+ *
+ * LICENSE: See the COPYING file included in this distribution.
+ *
+ * @access private
+ * @package OpenID
+ * @author JanRain, Inc. <openid@janrain.com>
+ * @copyright 2005-2008 Janrain, Inc.
+ * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
+ */
+
+require_once 'Auth/OpenID.php';
+require_once 'Auth/OpenID/BigMath.php';
+
+function Auth_OpenID_getDefaultMod()
+{
+    return '155172898181473697471232257763715539915724801'.
+        '966915404479707795314057629378541917580651227423'.
+        '698188993727816152646631438561595825688188889951'.
+        '272158842675419950341258706556549803580104870537'.
+        '681476726513255747040765857479291291572334510643'.
+        '245094715007229621094194349783925984760375594985'.
+        '848253359305585439638443';
+}
+
+function Auth_OpenID_getDefaultGen()
+{
+    return '2';
+}
+
+/**
+ * The Diffie-Hellman key exchange class.  This class relies on
+ * {@link Auth_OpenID_MathLibrary} to perform large number operations.
+ *
+ * @access private
+ * @package OpenID
+ */
+class Auth_OpenID_DiffieHellman {
+
+    var $mod;
+    var $gen;
+    var $private;
+    var $lib = null;
+
+    function Auth_OpenID_DiffieHellman($mod = null, $gen = null,
+                                       $private = null, $lib = null)
+    {
+        if ($lib === null) {
+            $this->lib = Auth_OpenID_getMathLib();
+        } else {
+            $this->lib = $lib;
+        }
+
+        if ($mod === null) {
+            $this->mod = $this->lib->init(Auth_OpenID_getDefaultMod());
+        } else {
+            $this->mod = $mod;
+        }
+
+        if ($gen === null) {
+            $this->gen = $this->lib->init(Auth_OpenID_getDefaultGen());
+        } else {
+            $this->gen = $gen;
+        }
+
+        if ($private === null) {
+            $r = $this->lib->rand($this->mod);
+            $this->private = $this->lib->add($r, 1);
+        } else {
+            $this->private = $private;
+        }
+
+        $this->public = $this->lib->powmod($this->gen, $this->private,
+                                           $this->mod);
+    }
+
+    function getSharedSecret($composite)
+    {
+        return $this->lib->powmod($composite, $this->private, $this->mod);
+    }
+
+    function getPublicKey()
+    {
+        return $this->public;
+    }
+
+    function usingDefaultValues()
+    {
+        return ($this->mod == Auth_OpenID_getDefaultMod() &&
+                $this->gen == Auth_OpenID_getDefaultGen());
+    }
+
+    function xorSecret($composite, $secret, $hash_func)
+    {
+        $dh_shared = $this->getSharedSecret($composite);
+        $dh_shared_str = $this->lib->longToBinary($dh_shared);
+        $hash_dh_shared = $hash_func($dh_shared_str);
+
+        $xsecret = "";
+        for ($i = 0; $i < Auth_OpenID::bytes($secret); $i++) {
+            $xsecret .= chr(ord($secret[$i]) ^ ord($hash_dh_shared[$i]));
+        }
+
+        return $xsecret;
+    }
+}
+
+
+