hash.php

<?php

class Hash extends Plugin
{
        public function pbkdf2($input, $s = null, $c = null, $kl = null, $a = null)
        {
                $s = is_null($s) ? $this->config['s'] : $this->pbkdf2($s);
                $c = is_null($c) ? $this->config['c'] : $c;
                $kl = is_null($kl) ? $this->config['kl'] : $kl;
                $a = is_null($a) ? $this->config['alg'] : $a;

                $hl = strlen(hash($this->config['alg'], null, true)); //hash length
                $kb = ceil($kl / $hl); //key blocks
                $dk = ''; //derived key

                for ($block = 1; $block <= $kb; $block ++)
                {
                        $ib = $b = hash_hmac($a, $s . pack('N', $block), $input, true);

                        for ($i = 1; $i < $c; $i++)
                        {
                                $ib ^= ($b = hash_hmac($a, $b, $input, true));
                        }

                        $dk .= $ib;
                }

                return base64_encode(substr($dk, 0, $kl));
        }
}