C#(TripleDES)对应Java(3DES)加密工具类

3DES又称Triple DES，是DES 加密算法的一种模式，它使用3条56位的密钥对3DES数据进行三次加密。

加密过程为：C=Ek3(Dk2(Ek1(P)))

解密过程为：P=Dk1(EK2(Dk3(C)))

C#已经对3DES加密进行了封装，可使用System.Security.Cryptography中的TripleDESCryptoServiceProvider类来实现，项目的需求是采用24位KEY、ECB模式来对应java平台的加解密。其中还涉及unix时间戳，MD5散列，base64编码的综合使用。

开始的时候对HttpWebRequest认识不深，在对base64的编码“+”符号上犯错，POST与GET请求中“+”【%2B】会出现替换的不同，以至于平台解析不成功。以下是测试后的代码：

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


namespace TestProject
{
	/// <summary>
	/// 数据加密工具类
	/// </summary>
	public sealed class EncryptionUtils
	{
		#region DES解密
		//3DES(DESede>Jave)24位KEY
		private const string ENCRYPT_KEY = "3DES_MD5_Timestamp123456";

		/// <summary>
		/// 3DES加密
		/// base64小细节，当使用get请求时，base64生成字符中有“+”号，
		/// 注意需要转换“%2B”，否则会被替换成空格。POST不存在
		/// while (str.IndexOf('+') != -1) {
		///	 str = str.Replace("+","%2B");
		//  }
		/// </summary>
		public static string Encrypt3DES (string fValue)
		{
			if(string.IsNullOrEmpty(fValue)){
				return fValue;
			}
			try{
				Encoding encoding = Encoding.GetEncoding("UTF-8");
				var DES = new TripleDESCryptoServiceProvider();
				DES.Key = encoding.GetBytes(ENCRYPT_KEY);
				DES.Mode = CipherMode.ECB;
				ICryptoTransform DESEncrypt = DES.CreateEncryptor();
				byte[] Buffer = encoding.GetBytes(fValue);
				return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));
			}catch(Exception ex){
				Log.Error("Encrypt3DES>>"+ex.Message);
				return string.Empty;
			}
		}

		/// <summary>
		/// 3DES解密
		/// </summary>
		/// <returns>解密串</returns>
		/// <param name="a_strString">加密串</param>
		public static string Decrypt3DES (string a_strString)
		{
			if(string.IsNullOrEmpty(a_strString)){
				return a_strString;
			}
			try {
				var DES = new TripleDESCryptoServiceProvider ();
				DES.Key = ASCIIEncoding.ASCII.GetBytes (ENCRYPT_KEY);
				DES.Mode = CipherMode.ECB;
				DES.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
				ICryptoTransform DESDecrypt = DES.CreateDecryptor ();
				byte[] Buffer = Convert.FromBase64String (a_strString);
				return ASCIIEncoding.ASCII.GetString (DESDecrypt.TransformFinalBlock (Buffer, 0, Buffer.Length));
			} catch (Exception e) {
				Log.Error("Decrypt3DES>>"+e.Message);
				return string.Empty;
			}
		}
		#endregion

		#region 基础方法
		/// <summary>
		/// MD5编码
		/// </summary>
		public static string MD5(string str){
			if(string.IsNullOrEmpty(str)){
				return str;
			}
			var md5 = new MD5CryptoServiceProvider();
			var datas = Encoding.UTF8.GetBytes(str);
			var hash = md5.ComputeHash(datas);
			md5.Clear();
			str = string.Empty;
			//把MD5所得用16进制小写的字符串形式，让函数返回一个32字节长的可打印字符串。
			for(int i =0;i<hash.Length;i++){
				str += hash[i].ToString("X").PadLeft(2,'0');
			}
			return str;
		}

		/// <summary>
		/// 并进行base64编码
		/// </summary>
		public static string ToBase64String(string str){
			if(string.IsNullOrEmpty(str)){
				return string.Empty;
			}
			return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
		}

		/// <summary>
		/// unix时间戳
		/// </summary>
		public static string GetTimestamp()
		{
			DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime (new System.DateTime (1970, 1, 1, 0, 0, 0, 0));
			DateTime nowTime = DateTime.Now;
			long unixTime = (long)Math.Round ((nowTime - startTime).TotalMilliseconds, MidpointRounding.AwayFromZero);
			return unixTime.ToString ();
		}
		#endregion
	}

	public static class Log
	{
		public static void Error(string msg)
		{
			Console.WriteLine ("Error"+msg);
		}

		public static void Info(string msg)
		{
			Console.WriteLine ("Info"+msg);
		}
	}
}

测试代码：

public static void Main (string[] args)
{
	Console.WriteLine ("Hello World!");

	string line = string.Empty;
	while ((line = Console.ReadLine ()) != null) {
		var encrypt = EncryptionUtils.Encrypt3DES (line);
		var decrypt = EncryptionUtils.Decrypt3DES (encrypt);
		Log.Info ("输入>>" + line);
		Log.Info ("密文>>" + encrypt);
		Log.Info ("明文>>" + decrypt);
	}
}