Java和C#中3DES的加密与解密

最近在工作中遇到将Java环境的一个用户ID用表单形式传递给.net环境做校验，考虑到不能将用户ID作为明文传递，因此利用简单的3DES进行加密解密操作。

需要注意的就是：

（1）两种环境下3DES加密解密的一致性问题：C#会对解密生成的byte在不满足长度16时，自动填充'/0'直至长度为16，因此在接收到Java端的加密数据后，我们要对生成的byte做处理把末尾的'\0'去掉。

（2）另外在传输上我们采用BASE64编码传输，一方面它具有简单的不可读性，另一方面它能规避一些特殊字符的传输问题。

下面的Java中3DES加密解密的示例代码：

import java.security.Key;
import java.io.IOException;
import java.security.InvalidKeyException;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.util.Scanner;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;



public class destest {
	
	
	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		byte[] key = new BASE64Decoder().decodeBuffer("YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4");
		byte[] keyiv = {1, 2, 3, 4, 5, 6, 7, 8};
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入加密前的字符串：");
		String str = sc.nextLine();
		System.out.println("原始字符串为： " + str);
		
		byte[] data = str.getBytes("UTF-8");
		
		System.out.println("开始CBC加密解密");
		
		byte[] strEncode = des3EncodeCBC(key, keyiv, data);
		System.out.println("以BASE64编码输出加密后的byte为：" + new BASE64Encoder().encode(strEncode));  
		for (int i = 0; i < strEncode.length; i++)                  // 输出加密后的strEncode每字节的内容
		{
			System.out.println("Encode byte[" + i + "]  " + strEncode[i]);
		}
		
		byte[] strDecode = des3DecodeCBC(key, keyiv, strEncode);
		String strGet = new String(strDecode, "UTF-8");
		System.out.println("解密后的字符串内容为：" + strGet);
		for (int i = 0; i < strDecode.length; i++)                  // 输出解密后strDecode每字节的内容
		{
			System.out.println("Decode byte[" + i + "]  " + strDecode[i]);
		}
		
		
	}
	
	public static byte[] des3EncodeCBC(byte[] key, byte[] keyiv, byte[] data) throws Exception
	{
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(keyiv);
		cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}
	
	public static byte[] des3DecodeCBC(byte[] key, byte[] keyiv, byte[] data) throws Exception
	{
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(keyiv);
		cipher.init(Cipher.DECRYPT_MODE, deskey, ips);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}
}

运行例子如下图所示：

下面是C#中3DES加密解密的示例代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Security.Cryptography;

namespace DES
{
    class Program
    {
        private static byte[] key = Convert.FromBase64String("YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4");
        private static byte[] iv = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
        public static byte[] Des3EncodeCBC(byte[] key, byte[] iv, byte[] data)
        {
            try
            {
                MemoryStream mStream = new MemoryStream();
                TripleDESCryptoServiceProvider tdsp = new TripleDESCryptoServiceProvider();
                tdsp.Mode = CipherMode.CBC;
                tdsp.Padding = PaddingMode.PKCS7;
                CryptoStream cStream = new CryptoStream(mStream, tdsp.CreateEncryptor(key, iv), CryptoStreamMode.Write);
                cStream.Write(data, 0, data.Length);
                cStream.FlushFinalBlock();
                byte[] ret = mStream.ToArray();
                cStream.Close();
                mStream.Close();
                return ret;
            }
            catch (CryptographicException e)
            {
                Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
                return null;
            }
        }

        public static byte[] Des3DecodeCBC(byte[] key, byte[] iv, byte[] data)
        {
            try
            {
                MemoryStream msDecrypt = new MemoryStream(data);
                TripleDESCryptoServiceProvider tdsp = new TripleDESCryptoServiceProvider();
                tdsp.Mode = CipherMode.CBC;
                tdsp.Padding = PaddingMode.PKCS7;
                CryptoStream csDecrypt = new CryptoStream(msDecrypt, tdsp.CreateDecryptor(key, iv), CryptoStreamMode.Read);

                byte[] fromEncrypt = new byte[data.Length];
                csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);
                return fromEncrypt;
            }
            catch(CryptographicException e)
            {
                Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
                return null;
            }
        }
 
        static void Main(string[] args)
        {
            System.Text.Encoding utf8 = System.Text.Encoding.UTF8;
            Console.WriteLine("请输入加密前的字符串：");
            string str = Console.ReadLine();
            Console.WriteLine("原始字符串为： " + str);

            byte[] data = utf8.GetBytes(str);

            System.Console.WriteLine("开始CBC加密解密");

            byte[] strEncode = Program.Des3EncodeCBC(key, iv, data);
            string base64Str = Convert.ToBase64String(strEncode);
            System.Console.WriteLine("以BASE64编码输出加密后的byte为：" + base64Str);
            for (int i = 0; i < strEncode.Length; i++)          // 输出加密后的strEncode每字节的内容
            {
                Console.WriteLine("Encode : byte[" + i + "]  " + strEncode[i]);
            }


            byte[] strDecode = Program.Des3DecodeCBC(key, iv, strEncode);
            string strGet = utf8.GetString(strDecode);
            Console.WriteLine("解密后的字符串内容为：" + strGet + "，长度为" + strGet.Length);
            for (int i = 0; i < strDecode.Length; i++)          // 输出加密后的strDecode每字节的内容
            {
                Console.WriteLine("Decode byte[" + i + "]  " + strDecode[i]);
            }


            // 去除生成byte的末尾的一些ASCII码为0的字符
            int len = 0;
            for (int i = 0; i < strDecode.Length; i++)
            {
                if (strDecode[i] != 0)
                    len++;
            }
            byte[] strDecodeEmit = new byte[len];
            for (int i = 0; i < len; i++)
            {
                strDecodeEmit[i] = strDecode[i];
            }
            System.Console.WriteLine("去掉末尾0后获得的字符串为：" + utf8.GetString(strDecodeEmit) + "，长度为：" + utf8.GetString(strDecodeEmit).Length);


            System.Console.ReadLine();
        }
    }
}

运行例子如下图所示：