新手求助:TripleDES要解密的数据的长度无效

2013-09-09 11:08:33 190 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

nuclear2011 墨衍会员 · AI 创作全网分发关注 + 加入社区

C#常用加密解密方法（TripleDES加密解密）本节主要分享TripleDES加密解密：DES，全称Data Encryption Standard，是一种对称加密算法。由于其安全性比较高（有限时间内,没有一种加密方法可以说是100%安全）,很可能是最广泛的密钥系统（我们公司也在用，估计你们也有在用....），唯一一种方法可以破解该算法，那就是穷举法。DES(Data Encryption Standard)和TripleDES是对称加密的两种实现。阅读详情

这个是逆向某个程序的代码,源代码经过混淆,整理过的代码如下

using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;



namespace Database4Test

{

    class Program

    {

        private static TripleDESCryptoServiceProvider tdes;

        private static SHA256Managed sha256;

        private static string magic;

        private static string delimiter;



        static Program()

        {

            tdes=new TripleDESCryptoServiceProvider();

            sha256=new SHA256Managed();

            magic = "fishDatabase";

        }



        static void Main(string[] args)

        {

            Console.Write("Please input your data:");

            string serial = Console.ReadLine();

            Console.WriteLine("Now compute serial:{0}", ComputeExpression(Encoding.UTF8.GetBytes(serial.Trim()), GetTripleDESKey(Encoding.UTF8.GetBytes(magic))));

            Console.ReadKey();

        }



        private static byte[] GetTripleDESKey(byte[] input)

        {

            int length = tdes.Key.Length;

            if (length != input.Length)

            {

                byte[] output = new byte[length];

                Array.Copy(sha256.ComputeHash(input), output, length - 1);

                return output;

            }

            return input;

        }



        private static byte[] GetTripleDESIV(byte[] input, int length)

        {

            byte[] output = new byte[length];

            Array.Copy(sha256.ComputeHash(Encoding.UTF8.GetBytes(Encoding.UTF8.GetString(input))), output, length - 1);

            return output;

        }



        private static string ComputeExpression(byte[] input1, byte[] input2)

        {

            ICryptoTransform transform = null;

            string str = string.Empty;

            try

            {

                byte[] buffer1 = Convert.FromBase64String(Encoding.UTF8.GetString(input1));

                using (MemoryStream ms = new MemoryStream(buffer1))

                {

                    byte[] buffer2 = new byte[buffer1.Length + 1];

                    transform = tdes.CreateDecryptor(input2, GetTripleDESIV(input2, tdes.IV.Length));

                    using (CryptoStream cs = new CryptoStream(ms, transform, CryptoStreamMode.Read))

                    {

                        cs.Read(buffer2, 0, buffer2.Length);

                    }

                    str = Encoding.UTF8.GetString(buffer2).Replace("\0", "");

                }

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex.Message);

            }

            finally

            {

                transform.Dispose();

            }

            return str;

        }

    }

}