System.Security.Cryptography.CryptographicException: '错误数据 ' - DES 加密

如何解决System.Security.Cryptography.CryptographicException: '错误数据 ' - DES 加密

我正在将一些代码从 Python 转换为 C#（.net framework 4.8、VS 2019、WIN 10）。一开始，我使用 DES CBC 加密数据并使用 DES ECB 解密。在中间，我有坏数据的例外。 我看到它可能连接到不同的键，但我不排除相同的结果，所以我不知道是什么原因造成的。

我无法比较结果，因为数据变量每次都是随机的。

密钥（cmacKey）为15522d4fca86042d，数据为93450567Â@ïÇpReAcTiV0000

private byte[] CBCMAC3DES(string cmacKey,string data){
        // pad by zeroes to multiple of eight
        string workDataStr = data;
        while ((workDataStr.Length / 2) % 8 != 0)
            workDataStr += "00";

        byte[] clearBytes = Str2byteArr(workDataStr);

        DESCryptoServiceProvider des = new DESCryptoServiceProvider();
        des.KeySize = 64;
        des.Mode = CipherMode.CBC;
        // taking only 8 chars from the key,convert to ascii and to byte array
        des.Key = Str2byteArr(HexStringToAsciString(cmacKey).Substring(0,8));
        des.IV = new byte[8] { 0,0 };

        ICryptoTransform ct = des.CreateEncryptor();
        byte[] resultArray = ct.TransformFinalBlock(clearBytes,clearBytes.Length);
        byte[] lastBlock = new byte[8];
        for (int i = 0; i < 8; i++)
            lastBlock[i] = resultArray[resultArray.Length - (8 - i)];

        // Decryption
        des.Mode = CipherMode.ECB;
        string s = cmacKey.Substring(8,8);
        byte[] keyTmpArr = Str2byteArr(s);
        des.Key = keyTmpArr;
        ct = des.CreateDecryptor();
        lastBlock = ct.TransformFinalBlock(lastBlock,lastBlock.Length);    // THE EXCEPTION

        des.Key = Str2byteArr(cmacKey.Substring(0,8));
        ct = des.CreateEncryptor();
        lastBlock = ct.TransformFinalBlock(lastBlock,lastBlock.Length);
        return lastBlock;

    }

这些是我调用的函数：

    public static byte[] Str2byteArr(string str)
    {
        byte[] ba = new byte[str.Length];
        for (int i = 0; i < str.Length; i++) ba[i] = Convert.ToByte(str[i]);
        return ba;
    }
    public string HexStringToAsciString(string hexString)
    {
        string ascii = string.Empty;
        for (int i = 0; i < hexString.Length; i += 2)
        {
            String hs = string.Empty;

            hs = hexString.Substring(i,2);
            uint decval = System.Convert.ToUInt32(hs,16);
            char character = System.Convert.ToChar(decval);
            ascii += character;

        }
        return ascii;
    }

这是 Python 代码，有帮助吗

def retail_mac(macKey,data,iv='\0'*8):
    workDataStr = pad_by_zeroes_to_multiple_of_eight(data)
    des = DES.new(str(macKey[0:8]),DES.MODE_CBC,IV = iv)
    res = des.encrypt(workDataStr)
    lastBlock = res[-8:]
    des = DES.new(str(macKey[8:16]),DES.MODE_ECB)
    lastBlock = des.decrypt(lastBlock)
    des = DES.new(str(macKey[0:8]),DES.MODE_ECB)
    return des.encrypt(lastBlock)

def pad_by_zeroes_to_multiple_of_eight(data):
    paddingSize = (8 - len(data)) % 8
    workData = bytearray(data)
    workData.extend('\0'*paddingSize)
    workDataStr = str(workData)
    return workDataStr

提前致谢