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Diffstat (limited to 'phpsec/Crypt/Random.php')
| -rw-r--r-- | phpsec/Crypt/Random.php | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/phpsec/Crypt/Random.php b/phpsec/Crypt/Random.php new file mode 100644 index 000000000..a91c4d3c5 --- /dev/null +++ b/phpsec/Crypt/Random.php @@ -0,0 +1,130 @@ +<?php
+/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
+
+/**
+ * Random Number Generator
+ *
+ * PHP versions 4 and 5
+ *
+ * Here's a short example of how to use this library:
+ * <code>
+ * <?php
+ * include('Crypt/Random.php');
+ *
+ * echo crypt_random();
+ * ?>
+ * </code>
+ *
+ * LICENSE: This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ * @category Crypt
+ * @package Crypt_Random
+ * @author Jim Wigginton <terrafrost@php.net>
+ * @copyright MMVII Jim Wigginton
+ * @license http://www.gnu.org/licenses/lgpl.txt
+ * @version $Id: Random.php,v 1.9 2010/04/24 06:40:48 terrafrost Exp $
+ * @link http://phpseclib.sourceforge.net
+ */
+
+/**
+ * Generate a random value.
+ *
+ * On 32-bit machines, the largest distance that can exist between $min and $max is 2**31.
+ * If $min and $max are farther apart than that then the last ($max - range) numbers.
+ *
+ * Depending on how this is being used, it may be worth while to write a replacement. For example,
+ * a PHP-based web app that stores its data in an SQL database can collect more entropy than this function
+ * can.
+ *
+ * @param optional Integer $min
+ * @param optional Integer $max
+ * @return Integer
+ * @access public
+ */
+function crypt_random($min = 0, $max = 0x7FFFFFFF)
+{
+ if ($min == $max) {
+ return $min;
+ }
+
+ // see http://en.wikipedia.org/wiki//dev/random
+ // if open_basedir is enabled file_exists() will ouput an "open_basedir restriction in effect" warning,
+ // so we suppress it.
+ if (@file_exists('/dev/urandom')) {
+ static $fp;
+ if (!$fp) {
+ $fp = fopen('/dev/urandom', 'rb');
+ }
+ extract(unpack('Nrandom', fread($fp, 4)));
+
+ // say $min = 0 and $max = 3. if we didn't do abs() then we could have stuff like this:
+ // -4 % 3 + 0 = -1, even though -1 < $min
+ return abs($random) % ($max - $min) + $min;
+ }
+
+ /* Prior to PHP 4.2.0, mt_srand() had to be called before mt_rand() could be called.
+ Prior to PHP 5.2.6, mt_rand()'s automatic seeding was subpar, as elaborated here:
+
+ http://www.suspekt.org/2008/08/17/mt_srand-and-not-so-random-numbers/
+
+ The seeding routine is pretty much ripped from PHP's own internal GENERATE_SEED() macro:
+
+ http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3_2/ext/standard/php_rand.h?view=markup */
+ if (version_compare(PHP_VERSION, '5.2.5', '<=')) {
+ static $seeded;
+ if (!isset($seeded)) {
+ $seeded = true;
+ mt_srand(fmod(time() * getmypid(), 0x7FFFFFFF) ^ fmod(1000000 * lcg_value(), 0x7FFFFFFF));
+ }
+ }
+
+ static $crypto;
+
+ // The CSPRNG's Yarrow and Fortuna periodically reseed. This function can be reseeded by hitting F5
+ // in the browser and reloading the page.
+
+ if (!isset($crypto)) {
+ $key = $iv = '';
+ for ($i = 0; $i < 8; $i++) {
+ $key.= pack('n', mt_rand(0, 0xFFFF));
+ $iv .= pack('n', mt_rand(0, 0xFFFF));
+ }
+ switch (true) {
+ case class_exists('Crypt_AES'):
+ $crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
+ break;
+ case class_exists('Crypt_TripleDES'):
+ $crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
+ break;
+ case class_exists('Crypt_DES'):
+ $crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
+ break;
+ case class_exists('Crypt_RC4'):
+ $crypto = new Crypt_RC4();
+ break;
+ default:
+ extract(unpack('Nrandom', pack('H*', sha1(mt_rand(0, 0x7FFFFFFF)))));
+ return abs($random) % ($max - $min) + $min;
+ }
+ $crypto->setKey($key);
+ $crypto->setIV($iv);
+ $crypto->enableContinuousBuffer();
+ }
+
+ extract(unpack('Nrandom', $crypto->encrypt("\0\0\0\0")));
+ return abs($random) % ($max - $min) + $min;
+}
+?>
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