<?php /** * CryptUtil: A suite of wrapper utility functions for the OpenID * library. * * 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 */ if (!defined('Auth_OpenID_RAND_SOURCE')) { /** * The filename for a source of random bytes. Define this yourself * if you have a different source of randomness. */ define('Auth_OpenID_RAND_SOURCE', '/dev/urandom'); } class Auth_OpenID_CryptUtil { /** * Get the specified number of random bytes. * * Attempts to use a cryptographically secure (not predictable) * source of randomness if available. If there is no high-entropy * randomness source available, it will fail. As a last resort, * for non-critical systems, define * <code>Auth_OpenID_RAND_SOURCE</code> as <code>null</code>, and * the code will fall back on a pseudo-random number generator. * * @param int $num_bytes The length of the return value * @return string $bytes random bytes */ function getBytes($num_bytes) { static $f = null; $bytes = ''; if ($f === null) { if (Auth_OpenID_RAND_SOURCE === null) { $f = false; } else { $f = @fopen(Auth_OpenID_RAND_SOURCE, "r"); if ($f === false) { $msg = 'Define Auth_OpenID_RAND_SOURCE as null to ' . ' continue with an insecure random number generator.'; trigger_error($msg, E_USER_ERROR); } } } if ($f === false) { // pseudorandom used $bytes = ''; for ($i = 0; $i < $num_bytes; $i += 4) { $bytes .= pack('L', mt_rand()); } $bytes = substr($bytes, 0, $num_bytes); } else { $bytes = fread($f, $num_bytes); } return $bytes; } /** * Produce a string of length random bytes, chosen from chrs. If * $chrs is null, the resulting string may contain any characters. * * @param integer $length The length of the resulting * randomly-generated string * @param string $chrs A string of characters from which to choose * to build the new string * @return string $result A string of randomly-chosen characters * from $chrs */ function randomString($length, $population = null) { if ($population === null) { return Auth_OpenID_CryptUtil::getBytes($length); } $popsize = strlen($population); if ($popsize > 256) { $msg = 'More than 256 characters supplied to ' . __FUNCTION__; trigger_error($msg, E_USER_ERROR); } $duplicate = 256 % $popsize; $str = ""; for ($i = 0; $i < $length; $i++) { do { $n = ord(Auth_OpenID_CryptUtil::getBytes(1)); } while ($n < $duplicate); $n %= $popsize; $str .= $population[$n]; } return $str; } } ?>