public function decodeReversibleString($string)
    {

        $salt = $this->getSecretAppString();

        $key = substr(base64_encode($salt), 0, 50);
        $iv = '12345678';
        $cc = base64_decode($string);

        $cipher = mcrypt_module_open(MCRYPT_BLOWFISH, '', 'cbc', '');

        mcrypt_generic_init($cipher, $key, $iv);
        $decrypted = mdecrypt_generic($cipher, $cc);
        mcrypt_generic_deinit($cipher);

        return json_decode(base64_decode($decrypted), true)['key'];
    }