Rijndael填充错误

时间：2011-02-07 19:51:27

标签： c# encryption aes rijndael

您好我正在尝试通过Rijaendal加密/解密字符串。 我根本无法弄清楚为什么解密会爆炸。我总是以不正确的填充错误结束。抛弃我的一件事是我的加密结果，我将其作为HEX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HEX转换时最终有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();
        }

    }
}

3 个答案:

答案 0 :(得分：5)

基本上你在文本和数据之间做了太多的转换。看看这个，例如：

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

一旦你有一个ASCII字符串，你为什么需要将那个转换成十六进制？它已经是文字了！但到那时你已经丢失了数据。除非你真的需要以十六进制（在这种情况下遵循Adam的建议并更改你的HexToAscii方法来取一个byte []而不是字符串）你应该只使用Convert.ToBase64String：

string encryptValue = Convert.ToBase64String(encBuffer);

解密时在另一端使用Convert.FromBase64String。然后，您可以完全摆脱十六进制方法。

哦，一般情况下我不会使用Encoding.ASCII开头...我几乎总是使用Encoding.UTF8代替。目前，您将无法加密（正确）包含非ASCII字符（如重音符号）的任何字符串。

这是您的测试程序的重新安装版本，其中包含一些更改。请注意，名称“密文”和“纯文本”是加密的......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);
        }
    }
}

答案 1 :(得分：2)

您不应该使用ASCII字符编码作为中间步骤;你应该改变你的函数，从十六进制到ASCII（再回来），从byte[]变为十六进制（再回来）。

    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形式而不是像Base64那样更紧凑？你在你的例子中使用Base64传输密钥和IV，所以我只是想知道是什么让你想在这里将加密数据作为十六进制返回。

无论如何，这里应该适合你：

    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);
    }

答案 2 :(得分：2)

您可以避免使用Decypting / Encrypting和使用System.Text.Encoding的问题并避免使用Base64编码，通过添加一些完全绕过System.Text.Encoding中微软不匹配转换的方法，允许您使用加密内存中的实际字节，无需任何翻译。

由于使用了这些，我避免了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());
    }

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;
    }
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