使用 TDES 加密和解密时出现错误数据答案

【问题标题】：Bad Data when Encrypt and Decrypt with TDES使用 TDES 加密和解密时出现错误数据
【发布时间】：2010-12-22 18:24:33
【问题描述】：

我正在使用 TDES 加密一个大字符串并尝试对其进行解密。无法理解出了什么问题。当它在解密中执行 READ 功能时，我从加密异常中得到“坏数据”。（我用cmets标记了这条线）

生成和加密字符串：

public void MssGenerateKeyPair(string ssSymmetricKey, out string ssCipheredKeyPair, out string ssPublicKey) {
        ssCipheredKeyPair = string.Empty;
        ssPublicKey = string.Empty;

        //Symmetric key is the hash of user's signing password
        SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
        byte[] tempKey = sha1.ComputeHash(Encoding.UTF8.GetBytes(ssSymmetricKey));
        byte[] key = new byte[24];
        tempKey.CopyTo(key, 0);
        //if symmetric keys is < 24
        for (int index = 0, i = tempKey.Length; i < key.Length; index++, i++)
        {
            key[i] = tempKey[index];
        }

        //define symmetric encryption data
        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = key;
        tdes.IV = new byte[8];
        tdes.Mode = CipherMode.CBC;
        tdes.Padding = PaddingMode.PKCS7;

        //define assymetric stuff
        RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
        MemoryStream memoryStream = new MemoryStream();
        CryptoStream cryptoStream = new CryptoStream(memoryStream, tdes.CreateEncryptor(), CryptoStreamMode.Write);
        byte[] toChipher = Encoding.UTF8.GetBytes(rsa.ToXmlString(true));
        cryptoStream.Write(toChipher, 0, toChipher.Length);
        byte[] cipheredKeyPair = memoryStream.ToArray();
        ssCipheredKeyPair = Convert.ToBase64String(cipheredKeyPair);
        ssPublicKey = rsa.ToXmlString(false);
        cryptoStream.Close();
        memoryStream.Close();


    } // MssGenerateKeyPair

解密字符串

public void MssSignData(string ssSymmetricKey, byte[] ssDataToSign, byte[] ssCipheredKeyPair, out byte[] ssSignature, out byte[] ssSignedData) {
        ssSignature = new byte[] {};
        ssSignedData = new byte[] {};

        //Symmetric key is the hash of user's signing password
        SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
        byte[] tempKey = sha1.ComputeHash(Encoding.UTF8.GetBytes(ssSymmetricKey));
        byte[] key = new byte[24];
        tempKey.CopyTo(key, 0);
        //if symmetric keys is < 24
        for (int index = 0, i = tempKey.Length; i < key.Length; index++, i++)
        {
            key[i] = tempKey[index];
        }

        //define symmetric encryption data
        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = key;
        tdes.IV = new byte[8];
        tdes.Mode = CipherMode.CBC;
        tdes.Padding = PaddingMode.PKCS7;

        MemoryStream memoryStream = new MemoryStream(ssCipheredKeyPair);
        CryptoStream cryptoStream = new CryptoStream(memoryStream, tdes.CreateDecryptor(), CryptoStreamMode.Read);
        MemoryStream plainMemoryStream = new MemoryStream();

        byte[] tempPlainBytes = new byte[1024];

        int read = 0;
        int totalRead = 0;
        do
        {
            //################################################################
            //ERROR IN THE FOLLOWING LINE
            //################################################################
            read = cryptoStream.Read(tempPlainBytes, 0, tempPlainBytes.Length);
            totalRead += read;
            plainMemoryStream.Write(tempPlainBytes, 0, read);
        } while (read > 0);

        RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
        rsa.FromXmlString(Encoding.UTF8.GetString(plainMemoryStream.ToArray()));

        ssSignature = rsa.SignData(ssDataToSign, new SHA1CryptoServiceProvider());
        ssSignedData = ssDataToSign;
        cryptoStream.Close();
        memoryStream.Close();
        plainMemoryStream.Close();

    } // MssSignData

要测试的代码

 private void button1_Click(object sender, EventArgs e)
    {
        string key;
        string pkey;
        byte[] sig;
        byte[] avs;

        OutSystems.NssPseudoCertificates.CssPseudoCertificates c = new OutSystems.NssPseudoCertificates.CssPseudoCertificates();

        c.MssGenerateKeyPair("xpto",out key, out pkey);
        c.MssSignString("xpto", "hello", key, out sig, out avs);


    }

【问题讨论】：

提示：您应该使用using 语句来处理流（和其他 IDisposable 资源）的关闭，以防引发异常。这可能不是您的问题，但它可以帮助您避免以后出现其他问题。 (msdn.microsoft.com/en-us/library/yh598w02(v=VS.100).aspx)
您可能想在内存流中添加“Flush”或在 encryptoStream 上添加“FlushFinalBlock”。 TDES 只是做了 3 次 DES，由于 DES 是一个块密码，我们需要确保它是“填充的块大小”。
@Marvin Smit：它使用 PKCS7 填充方案进行填充，并且 close() 应该刷新流。
@GregS：你是说我不应该使用 PKCS7？应该做什么？零点？

标签： c# encryption cryptographicexception tripledes

【解决方案1】：

就像 Marvin Smit 在他的 cmets 中所说的那样：添加同花，我做到了并且成功了！功劳归他所有！

【讨论】：