Rijndael 填充错误

Question

您好，我正在尝试通过 Rijaendal 加密/解密字符串。 我根本不明白为什么解密会失败。我总是会遇到不正确的填充错误。让我失望的一件事是我的加密结果，我将其作为十六进制数组返回。它的长度为 14 个字节。在我的解密函数中，相同的字节数组在从十六进制转换后最终有 16 个字节。

任何帮助将不胜感激：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace rjandal
{
    class Program
    {
        static void Main(string[] args)
        {
            string DataForEncrypting = "this is a test";

            string key = string.Empty;
            string iv = string.Empty;

            using (System.Security.Cryptography.RijndaelManaged rmt = new System.Security.Cryptography.RijndaelManaged())
            {
                rmt.KeySize = 256;
                rmt.BlockSize = 128;
                rmt.Mode = System.Security.Cryptography.CipherMode.CBC;
                rmt.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
                rmt.GenerateKey();
                rmt.GenerateIV();
                key = Convert.ToBase64String(rmt.Key);
                iv = Convert.ToBase64String(rmt.IV);
            }

            string encryptedData = _encrypt(DataForEncrypting, key, iv);
            string unencryptedData = _decrypt(key, iv, HexString2Ascii(encryptedData));

            Console.WriteLine(unencryptedData);
            Console.WriteLine(encryptedData);
            Console.ReadKey();
        }

        private static string _encrypt(string value, string key, string initVector)
        {
            byte[] buffer = ASCIIEncoding.ASCII.GetBytes(value);
            byte[] encBuffer;
            using (System.Security.Cryptography.RijndaelManaged rmt = new System.Security.Cryptography.RijndaelManaged())
            {
                rmt.KeySize = 256;
                rmt.BlockSize = 128;
                rmt.Mode = System.Security.Cryptography.CipherMode.CBC;
                rmt.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
                encBuffer = rmt.CreateEncryptor(Convert.FromBase64String(key),
                    Convert.FromBase64String(initVector)).TransformFinalBlock(buffer, 0, buffer.Length);
            }
            string encryptValue = ConvertToHex(ASCIIEncoding.ASCII.GetString(encBuffer));
            return encryptValue;
        }

        private static string _decrypt(string key, string initVector, string value)
        {
            byte[] hexBuffer = ASCIIEncoding.ASCII.GetBytes(value);
            byte[] decBuffer;
            using (System.Security.Cryptography.RijndaelManaged rmt = new System.Security.Cryptography.RijndaelManaged())
            {
                rmt.KeySize = 256;
                rmt.BlockSize = 128;
                rmt.Mode = System.Security.Cryptography.CipherMode.CBC;
                rmt.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
                decBuffer = rmt.CreateDecryptor(Convert.FromBase64String(key),
                    Convert.FromBase64String(initVector)).TransformFinalBlock(hexBuffer, 0, hexBuffer.Length);
            }

            return System.Text.ASCIIEncoding.ASCII.GetString(decBuffer);
        } 

        private static string ConvertToHex(string asciiString)
        {
            string hex = "";
            foreach (char c in asciiString)
            {
                int tmp = c;
                hex += String.Format("{0:x2}", (uint)System.Convert.ToUInt32(tmp.ToString()));
            }
            return hex;
        }

        private static string HexString2Ascii(string hexString)
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i <= hexString.Length - 2; i += 2)
            {
                sb.Append(Convert.ToString(Convert.ToChar(Int32.Parse(hexString.Substring(i, 2), System.Globalization.NumberStyles.HexNumber))));
            }
            return sb.ToString();
        }

    }
}

Answer 1

基本上，您在文本和数据之间进行了太多转换。例如，看看这个：

string encryptValue = ConvertToHex(ASCIIEncoding.ASCII.GetString(encBuffer));

一旦获得了 ASCII 字符串，为什么需要将它转换为十六进制？已经是文字了！但到那时你就已经丢失了数据。除非您真的需要十六进制（在这种情况下，请遵循 Adam 的建议并更改 HexToAscii 方法以采用 byte[] 而不是字符串），您应该只使用 Convert.ToBase64String：

string encryptValue = Convert.ToBase64String(encBuffer);

使用 Convert解密时另一端的.FromBase64String。然后你就可以完全摆脱你的十六进制方法了。

哦，一般来说，我不会使用 Encoding.ASCII 开头...我几乎总是使用 Encoding.UTF8 代替。目前，您将无法（正确）加密任何包含非 ASCII 字符（例如重音符号）的字符串。

这是测试程序的重新调整版本，其中进行了一些更改。请注意，名称“密文”和“纯文本”是在加密方面......它们仍然是二进制数据而不是文本！

using System;
using System.Security.Cryptography;
using System.Text;

class Program
{
    static void Main(string[] args)
    {
        string DataForEncrypting = "this is a test";

        string key = string.Empty;
        string iv = string.Empty;

        using (RijndaelManaged rmt = new RijndaelManaged())
        {
            rmt.KeySize = 256;
            rmt.BlockSize = 128;
            rmt.Mode = CipherMode.CBC;
            rmt.Padding = PaddingMode.ISO10126;
            rmt.GenerateKey();
            rmt.GenerateIV();
            key = Convert.ToBase64String(rmt.Key);
            iv = Convert.ToBase64String(rmt.IV);
        }

        string encryptedData = _encrypt(DataForEncrypting, key, iv);
        string unencryptedData = _decrypt(key, iv, encryptedData);

        Console.WriteLine(unencryptedData);
        Console.WriteLine(encryptedData);
        Console.ReadKey();
    }

    private static string _encrypt(string value, string key, string initVector)
    {
        using (RijndaelManaged rmt = new RijndaelManaged())
        {
            rmt.KeySize = 256;
            rmt.BlockSize = 128;
            rmt.Mode = CipherMode.CBC;
            rmt.Padding = PaddingMode.ISO10126;
            byte[] plainText = Encoding.UTF8.GetBytes(value);
            byte[] cipherText = rmt.CreateEncryptor(Convert.FromBase64String(key),
                                                    Convert.FromBase64String(initVector))
                                   .TransformFinalBlock(plainText, 0, plainText.Length);
            return Convert.ToBase64String(cipherText);
        }
    }

    private static string _decrypt(string key, string initVector, string value)
    {
        using (RijndaelManaged rmt = new RijndaelManaged())
        {
            rmt.KeySize = 256;
            rmt.BlockSize = 128;
            rmt.Mode = CipherMode.CBC;
            rmt.Padding = PaddingMode.ISO10126;
            byte[] cipherText = Convert.FromBase64String(value);
            byte[] plainText = rmt.CreateDecryptor(Convert.FromBase64String(key),
                                                   Convert.FromBase64String(initVector))
                                  .TransformFinalBlock(cipherText, 0, cipherText.Length);
            return Encoding.UTF8.GetString(plainText);
        }
    }
}

Answer 2

您不应该使用 ASCII 字符编码作为中间步骤；您应该将从十六进制转换为 ASCII（然后再返回）的函数更改为从 byte[] 转换为十六进制（然后再返回）。

    private static string ConvertToHex(byte[] data)
    {
        string hex = "";
        foreach (byte b in data)
        {
            hex += b.ToString("X2");
        }
        return hex;
    }

    private static byte[] HexString2ByteArray(string hexString)
    {
        byte[] output = new byte[hexString.Length / 2];

        for (int i = 0; i <= hexString.Length - 2; i += 2)
        {
             output[i/2] = Convert.ToByte(hexString.Substring(i, 2), 16);
        }
        return output;
    }

作为旁注，您是否有理由寻找数组的十六进制表示而不是像 Base64 这样更紧凑的东西？您在示例中使用 Base64 来传输密钥和 IV，所以我只是好奇是什么让您想要在此处以十六进制形式返回加密数据。

无论如何，以下内容应该对您有用：

    private static string _encrypt(string value, string key, string initVector)
    {
        byte[] buffer = Encoding.Unicode.GetBytes(value);
        byte[] encBuffer;
        using (System.Security.Cryptography.RijndaelManaged rmt = new System.Security.Cryptography.RijndaelManaged())
        {
            rmt.KeySize = 256;
            rmt.BlockSize = 128;
            rmt.Mode = System.Security.Cryptography.CipherMode.CBC;
            rmt.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
            encBuffer = rmt.CreateEncryptor(Convert.FromBase64String(key),
                Convert.FromBase64String(initVector)).TransformFinalBlock(buffer, 0, buffer.Length);
        }
        string encryptValue = ConvertToHex(encBuffer);
        return encryptValue;
    }

    private static string _decrypt(string key, string initVector, string value)
    {
        byte[] hexBuffer = HexString2ByteArray(value);
        byte[] decBuffer;
        using (System.Security.Cryptography.RijndaelManaged rmt = new System.Security.Cryptography.RijndaelManaged())
        {
            rmt.KeySize = 256;
            rmt.BlockSize = 128;
            rmt.Mode = System.Security.Cryptography.CipherMode.CBC;
            rmt.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
            decBuffer = rmt.CreateDecryptor(Convert.FromBase64String(key),
                Convert.FromBase64String(initVector)).TransformFinalBlock(hexBuffer, 0, hexBuffer.Length);
        }

        return Encoding.Unicode.GetString(decBuffer);
    } 

Answer 3

您可以避免解密/加密的问题，并使用 System.Text.Encoding 并避免使用 Base64 编码解决方法，方法是添加一些完全绕过 Microsoft 在 System.Text.Encoding 中不匹配的转换的方法，允许您加密真实的数据内存中的字节没有任何翻译。

由于使用这些，我避免了由 System.Text.Encoding 方法引起的填充错误，也没有使用 Base64 转换。

    private static Byte[] GetBytes(String SomeString)
    {
        Char[] SomeChars = SomeString.ToCharArray();
        Int32 Size = SomeChars.Length * 2;
        List<Byte> TempList = new List<Byte>(Size);
        foreach (Char Character in SomeChars)
        {
            TempList.AddRange(BitConverter.GetBytes(Character));
        }
        return TempList.ToArray();
    }
    private static String GetString(Byte[] ByteArray)
    {
        Int32 Size = ByteArray.Length / 2;
        List<Char> TempList = new List<Char>(Size);
        for (Int32 i = 0; i < ByteArray.Length; i += 2)
        {
            TempList.Add(BitConverter.ToChar(ByteArray, i));
        }
        return new String(TempList.ToArray());
    }

以及它们如何与加密一起使用

    private static String Encrypt(String Test1, Byte[] Key, Byte[] IV)
    {
        Byte[] Encrypted;
        using (AesCryptoServiceProvider AesMan = new AesCryptoServiceProvider())
        {
            AesMan.Mode              = CipherMode.CBC;
            AesMan.Padding           = PaddingMode.ISO10126;
            ICryptoTransform EncThis = AesMan.CreateEncryptor(Key, IV);

            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, EncThis, CryptoStreamMode.Write))
                {

                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        //Write all data to the stream.
                        swEncrypt.Write(Test1);
                    }
                    Encrypted = msEncrypt.ToArray();
                }
            }
        };
        return GetString(Encrypted);
    }

    private static String Decrypt(String Data, Byte[] Key, Byte[] IV)
    {
        String Decrypted;
        using (AesCryptoServiceProvider AesMan = new AesCryptoServiceProvider())
        {
            AesMan.Mode              = CipherMode.CBC;
            AesMan.Padding           = PaddingMode.ISO10126;
            ICryptoTransform EncThis = AesMan.CreateDecryptor(Key, IV);

            using (MemoryStream msDecrypt = new MemoryStream(GetBytes(Data)))
            {
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, EncThis, CryptoStreamMode.Read))
                {
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                    {

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