laravel framework session id decryption algorithm

$encrypter = new Illuminate\Encryption\Encrypter('qianzhudecangshu');
        $session_filename = $encrypter->decrypt($_COOKIE['cangshu']);
        var_dump($session_filename);exit;

The above one is a third-party library https://github.com/illuminate/encryption. The solution is actually just a package that relies on laravel’s built-in implementation, which is useless

The following one is the built-in library of laravel 4.1

$b = Crypt::decrypt($_COOKIE['cangshu']);
dump($b);
$a = Crypt::encrypt('96c65a2077a21ad8e960ba1078641f90e2d93aa1');
dump($a);
$c = Crypt::decrypt($a);
dump($c);