<?php // PHP 5.4 if (!function_exists('hex2bin')) { function hex2bin($data) { return pack("H*" , $hex_string); } } // PHP 5.6 if (!function_exists('hash_equals')) { function hash_equals($ours, $theirs) { $ours = (string)$ours; $theirs = (string)$theirs; $tlen = strlen($theirs); $olen = strlen($ours); $answer = 0; for ($i = 0; $i < $tlen; $i++) { $answer |= ord($ours[$olen > $i ? $i : 0]) ^ ord($theirs[$i]); } return $answer === 0 && $olen === $tlen; } }