Java 以 DES 加密，C# 解密

工作上，別的系統以java 實作，但我們的系統仍以 dotnet 實作。問題來了，需要加解密。試了幾次，答案如下。

import javax.crypto.*;
import javax.crypto.spec.*;

public class TestMain {
	public static void main(String[] args) throws Exception
    {
		byte[] rgbIV = {(byte)11, (byte)12,(byte)13,(byte)14,
				(byte)15,(byte)16,(byte)17,(byte)18};
		
		byte[] rgbKey = {(byte)21, (byte)22,(byte)23,(byte)24,
				(byte)25,(byte)26,(byte)27,(byte)28};
		
		byte[] encrypedBytes = desEncrypt("AB123456", rgbKey, rgbIV );
		String encrypedString = new sun.misc.BASE64Encoder().encode(encrypedBytes);
		System.out.println(encrypedString);
	}
	
	
	public static byte[] desEncrypt(String message, byte[] rgbKey, byte[] rgbIV) throws Exception {
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		DESKeySpec desKeySpec = new DESKeySpec(rgbKey);
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
		IvParameterSpec iv = new IvParameterSpec(rgbIV);
		cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
		return cipher.doFinal(message.getBytes("UTF-8"));
	}
}

加密後的字串為 uv0cplrvtQ9KnRXKKd+MuQ==

使用 c# 來解密。當然需要使用同一把key

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

namespace ConsoleApplication13
{
  class Program
  {
    static void Main(string[] args)
    {
      byte[] rgbIV = {(byte)11, (byte)12,(byte)13,(byte)14,
				(byte)15,(byte)16,(byte)17,(byte)18};

      byte[] rgbKey = {(byte)21, (byte)22,(byte)23,(byte)24,
				(byte)25,(byte)26,(byte)27,(byte)28};

      string reslut = DecryptString("uv0cplrvtQ9KnRXKKd+MuQ==", rgbIV, rgbKey);
      Console.WriteLine(reslut);
    }


    /// 
   
    /// DES解密字符串   
    /// 
   
    /// 待解密的字符串   
    /// 解密密鑰,要求為8位,和加密密鑰相同   
    /// 解密成功返回解密後的字符串   
    public static string DecryptString(string cipherText, byte[] rgbIV, byte[] rgbKey)
    {
      byte[] inputByteArray = Convert.FromBase64String(cipherText);
      DESCryptoServiceProvider dcsp = new DESCryptoServiceProvider();
      MemoryStream mStream = new MemoryStream();
      CryptoStream cStream = new CryptoStream(mStream, dcsp.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
      cStream.Write(inputByteArray, 0, inputByteArray.Length);
      cStream.FlushFinalBlock();
      return Encoding.UTF8.GetString(mStream.ToArray());
    }
  }
}

最近這裡寫的比我更詳細，請參考