1<?php
2
3/**
4 * The OpenID library's Diffie-Hellman implementation.
5 *
6 * PHP versions 4 and 5
7 *
8 * LICENSE: See the COPYING file included in this distribution.
9 *
10 * @access private
11 * @package OpenID
12 * @author JanRain, Inc. <openid@janrain.com>
13 * @copyright 2005-2008 Janrain, Inc.
14 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
15 */
16
17require_once 'Auth/OpenID.php';
18require_once 'Auth/OpenID/BigMath.php';
19
20function Auth_OpenID_getDefaultMod()
21{
22    return '155172898181473697471232257763715539915724801'.
23        '966915404479707795314057629378541917580651227423'.
24        '698188993727816152646631438561595825688188889951'.
25        '272158842675419950341258706556549803580104870537'.
26        '681476726513255747040765857479291291572334510643'.
27        '245094715007229621094194349783925984760375594985'.
28        '848253359305585439638443';
29}
30
31function Auth_OpenID_getDefaultGen()
32{
33    return '2';
34}
35
36/**
37 * The Diffie-Hellman key exchange class.  This class relies on
38 * {@link Auth_OpenID_MathLibrary} to perform large number operations.
39 *
40 * @access private
41 * @package OpenID
42 */
43class Auth_OpenID_DiffieHellman {
44
45    public $mod;
46    public $gen;
47    public $private;
48    /** @var Auth_OpenID_BcMathWrapper */
49    public $lib = null;
50
51    function __construct($mod = null, $gen = null,
52                                       $private = null, $lib = null)
53    {
54        if ($lib === null) {
55            $this->lib = Auth_OpenID_getMathLib();
56        } else {
57            $this->lib = $lib;
58        }
59
60        if ($mod === null) {
61            $this->mod = $this->lib->init(Auth_OpenID_getDefaultMod());
62        } else {
63            $this->mod = $mod;
64        }
65
66        if ($gen === null) {
67            $this->gen = $this->lib->init(Auth_OpenID_getDefaultGen());
68        } else {
69            $this->gen = $gen;
70        }
71
72        if ($private === null) {
73            $r = $this->lib->rand($this->mod);
74            $this->private = $this->lib->add($r, 1);
75        } else {
76            $this->private = $private;
77        }
78
79        $this->public = $this->lib->powmod($this->gen, $this->private,
80                                           $this->mod);
81    }
82
83    function getSharedSecret($composite)
84    {
85        return $this->lib->powmod($composite, $this->private, $this->mod);
86    }
87
88    function getPublicKey()
89    {
90        return $this->public;
91    }
92
93    function usingDefaultValues()
94    {
95        return ($this->mod == Auth_OpenID_getDefaultMod() &&
96                $this->gen == Auth_OpenID_getDefaultGen());
97    }
98
99    function xorSecret($composite, $secret, $hash_func)
100    {
101        $dh_shared = $this->getSharedSecret($composite);
102        $dh_shared_str = $this->lib->longToBinary($dh_shared);
103        $hash_dh_shared = $hash_func($dh_shared_str);
104
105        $xsecret = "";
106        for ($i = 0; $i < Auth_OpenID::bytes($secret); $i++) {
107            $xsecret .= chr(ord($secret[$i]) ^ ord($hash_dh_shared[$i]));
108        }
109
110        return $xsecret;
111    }
112}
113
114
115