PHP AES/ECB 128加密

class Security {
    public static function encrypt($input, $key) {
    $key=md5($key.md5($key));
    $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
    $input = Security::pkcs5_pad($input, $size);
    $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');
    $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
    mcrypt_generic_init($td, $key, $iv);
    $data = mcrypt_generic($td, $input);
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);
    $data = base64_encode($data);
    return $data;
    }

    private static function pkcs5_pad ($text, $blocksize) {
        $pad = $blocksize - (strlen($text) % $blocksize);
        return $text . str_repeat(chr($pad), $pad);
    }

    public static function decrypt($dStr, $dKey) {
        $dKey=md5($dKey.md5($dKey));
        $decrypted= mcrypt_decrypt(MCRYPT_RIJNDAEL_128,$dKey,base64_decode($dStr),MCRYPT_MODE_ECB);
         $dec_s = strlen($decrypted);
        $padding = ord($decrypted[$dec_s-1]);
        $decrypted = substr($decrypted, 0, -$padding);
        return $decrypted;
    }
}