PHP에서 간단한 양방향 암호화 및 인증을 어떻게 구현할 수 있습니까?

class UnsafeCrypto
{
    const METHOD = 'aes-256-ctr';

    public static function encrypt($message, $key, $encode = false)
    {
        // ...
        if ($encode) {
            return base64_encode($nonce.$ciphertext);
        }
        return $nonce.$ciphertext;
    }

    public static function decrypt($message, $key, $encoded = false)
    {
        // ...
        $plaintext = openssl_decrypt(
            $ciphertext,
            self::METHOD,
            $key,
            OPENSSL_RAW_DATA,
            $nonce
        );
        
        return $plaintext;
    }
}

class SaferCrypto extends UnsafeCrypto
{
    const HASH_ALGO = 'sha256';

    public static function encrypt($message, $key, $encode = false)
    {
        // ...
        if ($encode) {
            return base64_encode($mac.$ciphertext);
        }
        // Prepend MAC to the ciphertext and return to caller
        return $mac.$ciphertext;
    }

    public static function decrypt($message, $key, $encoded = false)
    {
        // ...
        $calculated = hash_hmac(
            self::HASH_ALGO,
            $ciphertext,
            $authKey,
            true
        );
        
        if (!self::hashEquals($mac, $calculated)) {
            throw new Exception('Encryption failure');
        }
        
        // Pass to UnsafeCrypto::decrypt
        $plaintext = parent::decrypt($ciphertext, $encKey);
        
        return $plaintext;
    }
}