October 21st, 2010 Java解密C#DES加密数据

早晨的时候，一个朋友在MSN上问我.NET的DES算法实现。我说，这不是很简单的，.NET Framework都有现成的封装直接用就可以了。仔细一问，原来他要和一个.NET实现的系统进行数据交换，他的DES的Java实现出来的结果和.NET的不一样。所以，他怀疑.NET那边的实现有问题。好吧，程序员们都是如此自负，自己从来都不会出问题的-_-||

DES算是相当成熟的算法了，就不再赘述了。要加密结果一样，其实很简单，只要IV值和密钥一样，出来的结果应该都是一样的。看到他那边的.NET实现之后，IV是一个空的byte数组，Java这边只要也把IV的值设为空的byte数组的，结果应该就是一样的。思路就是这样的，下面就是实现了。

.NET的DES算法实现

根据密钥加密字符串

public static string EncryptDES(string encryptString, string encryptKey){    DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();    byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey);    byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);    MemoryStream mStream = new MemoryStream();    CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, new byte[8]), CryptoStreamMode.Write);    cStream.Write(inputByteArray, 0, inputByteArray.Length);    cStream.FlushFinalBlock();     return Convert.ToBase64String(mStream.ToArray());} 

根据密钥解密字符串

public static string DecryptDES(string decryptString, string decryptKey){    byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);    byte[] inputByteArray = Convert.FromBase64String(decryptString);    DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();    MemoryStream mStream = new MemoryStream();    CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, new byte[8]), CryptoStreamMode.Write);    cStream.Write(inputByteArray, 0, inputByteArray.Length);    cStream.FlushFinalBlock();    return Encoding.UTF8.GetString(mStream.ToArray());} 

Java的DES算法实现

根据密钥加密字符串

public static String encryptDES(String encryptString, String encryptKey) throws Exception {IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);byte[] encryptedData = cipher.doFinal(encryptString.getBytes()); return new BASE64Encoder().encode(encryptedData);} 

根据密钥解密字符串

public static String decryptDES(String decryptString, String decryptKey) throws Exception {byte[] byteMi = new BASE64Decoder().decodeBuffer(decryptString);IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);SecretKeySpec key = new SecretKeySpec(decryptKey.getBytes(), "DES");Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);byte decryptedData[] = cipher.doFinal(byteMi); return new String(decryptedData);} 

其实这个问题并不难解决，只是网上一些DES的算法的例子代码并没有用到IV，容易让人产生误解。