【知識積累】DES演算法之C#加密&Java解密

一、前言

　　在專案需要新增安全模組，客戶端呼叫服務端釋出的service必須要經過驗證，加密演算法採用DES，客戶端採用C#進行加密，服務端使用Java進行解密。廢話不多說，直接上程式碼。

二、客戶端

　　客戶端採用C#進行開發，C#進行DES加密解密程式碼清單如下：　

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

namespace DESHelper
{
    public class DESHelper
    {
        private static string m_encryptkey = "ENCRYPTT";
        private static string m_str = "IAMACOEDR";

        public static string DESEncrypt()
        {
            string str = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + m_str;
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(str);
            //建立加密物件的金鑰和偏移量    
            //原文使用ASCIIEncoding.ASCII方法的GetBytes方法    
            //使得輸入密碼必須輸入英文文字    
            des.Key = ASCIIEncoding.ASCII.GetBytes(m_encryptkey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(m_encryptkey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }

        public static string DESDecrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }

        static void Main(string[] args)
        {
            string str = DESEncrypt();
            Console.WriteLine(str);
            Console.WriteLine(DESDecrypt(str, m_encryptkey));
        }
    }
}

　　執行結果：

　　34DB26C86E933FB8F9C294A563BEF742D85451292A3C40C6FC8DF5A99C56EDCC
　　2016-03-10 12:43:05IAMACOEDR

三、伺服器

　　伺服器採用Java進行開發，Java進行DES加密解密程式碼清單如下：　

import javax.crypto.SecretKey;   
import javax.crypto.SecretKeyFactory;   
import javax.crypto.spec.DESKeySpec;   
import javax.crypto.spec.IvParameterSpec;  
import java.security.Key;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.Cipher;

public class Des {       
    //解密資料   
    public static String decrypt(String message,String key) throws Exception {                
        byte[] bytesrc =convertHexString(message);      
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");       
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));      
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");      
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);      
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));                      
        cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);                       
        byte[] retByte = cipher.doFinal(bytesrc);   
        
        return new String(retByte);    
    }  
    
    // 加密資料
    public static byte[] encrypt(String message, String key)   
            throws Exception {   
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");   
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));      
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");   
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);   
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));   
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);   
   
        return cipher.doFinal(message.getBytes("UTF-8"));   
    }   
        
    public static byte[] convertHexString(String ss) {    
        byte digest[] = new byte[ss.length() / 2];    
        for(int i = 0; i < digest.length; i++) {    
            String byteString = ss.substring(2 * i, 2 * i + 2);    
            int byteValue = Integer.parseInt(byteString, 16);    
            digest[i] = (byte)byteValue;    
        }    
   
        return digest;    
    }  

    public static String toHexString(byte b[]) {   
        StringBuffer hexString = new StringBuffer();   
        for (int i = 0; i < b.length; i++) {   
            String plainText = Integer.toHexString(0xff & b[i]);   
            if (plainText.length() < 2)   
                plainText = "0" + plainText;   
            hexString.append(plainText);   
        }   
            
        return hexString.toString();   
    }       
      
    public static void main(String[] args) throws Exception {   
        String key = "ENCRYPTT";   
        String value = "IAMACODER";   
        String formatString = java.net.URLEncoder.encode(value, "utf-8");             
        System.out.println("加密資料:"+ formatString);   
        String encryptedString = toHexString(encrypt(formatString, key));                    
        System.out.println("加密後的資料為:" + encryptedString);   
        String decryptedString = java.net.URLDecoder.decode(decrypt(encryptedString, key), "utf-8") ;   
        System.out.println("解密後的資料:" + decryptedString);     
    }    
}

　　執行結果：

　　加密資料:IAMACODER
　　加密後的資料為:a8a3f8641ec18ddeff808105c493510e
　　解密後的資料:IAMACODER

四、測試C#加密&Java解密

　　將C#端加密的字串傳入Java端(替換decrypt中的encryptedString即可)直接進行解密，可以得到如下結果：

　　加密資料:IAMACODER
　　加密後的資料為:a8a3f8641ec18ddeff808105c493510e
　　解密後的資料:2016-03-10 12:43:05IAMACOEDR

五、總結

　　這是一個小的功能模組，有此需求的園友可以直接拿去使用，謝謝各位園友觀看~