Rijndael填充错误

Question

您好我正在尝试通过Rijaendal加密/解密字符串.我简直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转换时最终具有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,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));

一旦你得到了一个ASCII字符串,为什么你需要转换的是为十六进制？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);

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

哦,一般来说我不会用Encoding.ASCII...开始......我几乎总是用它Encoding.UTF8来代替.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调整版本,其中包含一些更改.请注意,名称"密文"和"纯文本"是加密方面的...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);
        }
    }
}