c# - 为什么 RijndaelManaged 加密后返回垃圾数据？

Question

我已经从 http://msdn.microsoft.com/en-us/library/system.security.cryptography.cryptostream.aspx 中获取了解密代码并修改如下。我有一个加密的例子，它在解码时工作得很好。但是当使用加密函数时，它返回带有奇怪符号的垃圾字符串。下面是加密/解密函数。

加密字符串“hey”的示例:“???U?b???z?Y???”
再次解码时: "ûc{ÁpÅ`ñ""Â"

我正在使用这段代码将字节数组转换为字符串:

private string ByteArrayToString(byte[] input)
    {
        ASCIIEncoding dec = new ASCIIEncoding();
        return dec.GetString(input);
    }

这里是加密/解密函数。解密功能工作正常。

private string DecryptStringFromBytesAes(byte[] cipherText, byte[] Key, byte[] IV)
    {
        // Check arguments. 
        if (cipherText == null || cipherText.Length <= 0)
            throw new ArgumentNullException("cipherText");
        if (Key == null || Key.Length <= 0)
            throw new ArgumentNullException("Key");

        // Declare the string used to hold 
        // the decrypted text.
        string plaintext = null;

        // Create an RijndaelManaged object 
        // with the specified key and IV. 
        using (RijndaelManaged aesAlg = new RijndaelManaged())
        {
            aesAlg.Key = Key;
            aesAlg.Padding = PaddingMode.Zeros;
            aesAlg.Mode = CipherMode.ECB;

            // Create a decrytor to perform the stream transform.
            ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

            // Create the streams used for decryption. 
            using (MemoryStream msDecrypt = new MemoryStream(cipherText))
            {
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                    {

                        // Read the decrypted bytes from the decrypting stream 
                        // and place them in a string.
                        plaintext = srDecrypt.ReadToEnd();
                    }
                }
            }

        }

        return plaintext;

    }




private byte[] EncryptStringToBytesAes(string plainText, byte[] Key, byte[] IV)
    {
        // Check arguments. 
        if (plainText == null || plainText.Length <= 0)
            throw new ArgumentNullException("plainText");
        if (Key == null || Key.Length <= 0)
            throw new ArgumentNullException("Key");
        byte[] encrypted;
        // Create an RijndaelManaged object 
        // with the specified key and IV. 
        using (RijndaelManaged aesAlg = new RijndaelManaged())
        {
            aesAlg.Key = Key;
            aesAlg.Padding = PaddingMode.Zeros;
            aesAlg.Mode = CipherMode.ECB;
            // Create a decrytor to perform the stream transform.
            ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

            // Create the streams used for encryption. 
            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {

                        //Write all data to the stream.
                        swEncrypt.Write(plainText);
                    }
                    encrypted = msEncrypt.ToArray();
                }
            }
        }
        return encrypted;

    }

Answer 1

您观察到的是将任意字节(在 0-255 范围内)映射到字符的问题。有意义的字符仅在 32-255 范围内，甚至仅在 32-127 (ASCII) 范围内。低于 32 的值是所谓的不可打印字符，高于 127 的值取决于您使用的字符编码。这就是加密文本看起来像垃圾的原因。因此，Mast 密码系统将字节转换为合理的 ASCII 范围。一种这样的算法是 BASE64。因此，通过 BASE64 处理加密的字节会得到所有可打印的字符，并且可以毫无问题地通过电子邮件发送。在解密之前，您必须撤消 BASE64 编码。

另一种使加密结果看起来更好的方法是显示它的十六进制表示。例如，如果您的字节值为 15，则打印 0F。您可以使用它来表示您的十六进制字节数组:

private string ByteArrayToHexString(byte[] data)
{
    return String.Concat(data.Select(b => b.ToString("x2")));
}