wpide / git / phpseclib / Crypt / Random.php

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1	<?php
2	/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
3
4	/**
5	* Random Number Generator
6	*
7	* PHP versions 4 and 5
8	*
9	* Here's a short example of how to use this library:
10	* <code>
11	* <?php
12	* include('Crypt/Random.php');
13	*
14	* echo crypt_random();
15	* ?>
16	* </code>
17	*
18	* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
19	* of this software and associated documentation files (the "Software"), to deal
20	* in the Software without restriction, including without limitation the rights
21	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
22	* copies of the Software, and to permit persons to whom the Software is
23	* furnished to do so, subject to the following conditions:
24	*
25	* The above copyright notice and this permission notice shall be included in
26	* all copies or substantial portions of the Software.
27	*
28	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
29	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
31	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
32	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
33	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
34	* THE SOFTWARE.
35	*
36	* @category Crypt
37	* @package Crypt_Random
38	* @author Jim Wigginton <terrafrost@php.net>
39	* @copyright MMVII Jim Wigginton
40	* @license http://www.opensource.org/licenses/mit-license.html MIT License
41	* @version $Id: Random.php,v 1.9 2010/04/24 06:40:48 terrafrost Exp $
42	* @link http://phpseclib.sourceforge.net
43	*/
44
45	/**
46	* Generate a random value.
47	*
48	* On 32-bit machines, the largest distance that can exist between $min and $max is 2**31.
49	* If $min and $max are farther apart than that then the last ($max - range) numbers.
50	*
51	* Depending on how this is being used, it may be worth while to write a replacement. For example,
52	* a PHP-based web app that stores its data in an SQL database can collect more entropy than this function
53	* can.
54	*
55	* @param optional Integer $min
56	* @param optional Integer $max
57	* @return Integer
58	* @access public
59	*/
60	function crypt_random($min = 0, $max = 0x7FFFFFFF)
61	{
62	if ($min == $max) {
63	return $min;
64	}
65
66	if (function_exists('openssl_random_pseudo_bytes')) {
67	// openssl_random_pseudo_bytes() is slow on windows per the following:
68	// http://stackoverflow.com/questions/1940168/openssl-random-pseudo-bytes-is-slow-php
69	if ((PHP_OS & "\xDF\xDF\xDF") !== 'WIN') { // PHP_OS & "\xDF\xDF\xDF" == strtoupper(substr(PHP_OS, 0, 3)), but a lot faster
70	extract(unpack('Nrandom', openssl_random_pseudo_bytes(4)));
71
72	return abs($random) % ($max - $min) + $min;
73	}
74	}
75
76	// see http://en.wikipedia.org/wiki//dev/random
77	static $urandom = true;
78	if ($urandom === true) {
79	// Warning's will be output unles the error suppression operator is used. Errors such as
80	// "open_basedir restriction in effect", "Permission denied", "No such file or directory", etc.
81	$urandom = @fopen('/dev/urandom', 'rb');
82	}
83	if (!is_bool($urandom)) {
84	extract(unpack('Nrandom', fread($urandom, 4)));
85
86	// say $min = 0 and $max = 3. if we didn't do abs() then we could have stuff like this:
87	// -4 % 3 + 0 = -1, even though -1 < $min
88	return abs($random) % ($max - $min) + $min;
89	}
90
91	/* Prior to PHP 4.2.0, mt_srand() had to be called before mt_rand() could be called.
92	Prior to PHP 5.2.6, mt_rand()'s automatic seeding was subpar, as elaborated here:
93
94	http://www.suspekt.org/2008/08/17/mt_srand-and-not-so-random-numbers/
95
96	The seeding routine is pretty much ripped from PHP's own internal GENERATE_SEED() macro:
97
98	http://svn.php.net/viewvc/php/php-src/tags/php_5_3_2/ext/standard/php_rand.h?view=markup */
99	if (version_compare(PHP_VERSION, '5.2.5', '<=')) {
100	static $seeded;
101	if (!isset($seeded)) {
102	$seeded = true;
103	mt_srand(fmod(time() * getmypid(), 0x7FFFFFFF) ^ fmod(1000000 * lcg_value(), 0x7FFFFFFF));
104	}
105	}
106
107	static $crypto;
108
109	// The CSPRNG's Yarrow and Fortuna periodically reseed. This function can be reseeded by hitting F5
110	// in the browser and reloading the page.
111
112	if (!isset($crypto)) {
113	$key = $iv = '';
114	for ($i = 0; $i < 8; $i++) {
115	$key.= pack('n', mt_rand(0, 0xFFFF));
116	$iv .= pack('n', mt_rand(0, 0xFFFF));
117	}
118	switch (true) {
119	case class_exists('Crypt_AES'):
120	$crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
121	break;
122	case class_exists('Crypt_TripleDES'):
123	$crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
124	break;
125	case class_exists('Crypt_DES'):
126	$crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
127	break;
128	case class_exists('Crypt_RC4'):
129	$crypto = new Crypt_RC4();
130	break;
131	default:
132	extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7FFFFFFF)))));
133	return abs($random) % ($max - $min) + $min;
134	}
135	$crypto->setKey($key);
136	$crypto->setIV($iv);
137	$crypto->enableContinuousBuffer();
138	}
139
140	extract(unpack('Nrandom', $crypto->encrypt("\0\0\0\0")));
141	return abs($random) % ($max - $min) + $min;
142	}
143