Here is a simple backporting function, it works for PHP >= 5.1<?phpif (!function_exists('random_int')) { function random_int($min, $max) { if (!function_exists('mcrypt_create_iv')) { trigger_error( 'mcrypt must be loaded for random_int to work', E_USER_WARNING ); return null; } if (!is_int($min) || !is_int($max)) { trigger_error('$min and $max must be integer values', E_USER_NOTICE); $min = (int)$min; $max = (int)$max; } if ($min > $max) { trigger_error('$max can\'t be lesser than $min', E_USER_WARNING); return null; } $range = $counter = $max - $min; $bits = 1; while ($counter >>= 1) { ++$bits; } $bytes = (int)max(ceil($bits/8), 1); $bitmask = pow(2, $bits) - 1; if ($bitmask >= PHP_INT_MAX) { $bitmask = PHP_INT_MAX; } do { $result = hexdec( bin2hex( mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM) ) ) & $bitmask; } while ($result > $range); return $result + $min; }}?>Randomness test<?php$max = 100; $test = 1000000;$array = array_fill(0, $max, 0);for ($i = 0; $i < $test; ++$i) { ++$array[random_int(0, $max-1)];}function arrayFormatResult(&$item) { global $test, $max; $perc = ($item/($test/$max))-1; $item .= ' '. number_format($perc, 4, '.', '') .'%';}array_walk($array, 'arrayFormatResult');print_r($array);?>