在一个项目中，要求C#和Java交互，为了保障数据的安全传输，我们用到DES加密。
在DES加密中，要求指定Key，IV，CipherMode（CBC），PaddingMode。Key和IV，CipherMode都好说，只是PaddingMode不好指定，因为C#的模式有：ANSIX923、ISO10126、None、PKCS7、Zero，而Java有：OAEPWith<digest>And<mgf>Padding、PKCS5Padding、SSL3Padding，没有交集呀。
我用C＃先写出来的，PaddingMode = PKCS7，Java方的不好作了。没有办法，只好帮人家写一个Java的例子，于是有了下面的代码：（Java高手不要笑话呀）
import java.io.*; import java.security.spec.*; import javax.crypto.*; import javax.crypto.spec.*; import sun.misc.BASE64Encoder; 
/*
作者:阿牛(牛昆亮) QQ:273352165 MSN:niukl@hotmail.com 声明:可以免费使用,请您保留此信息 如果您有什么改过,记得告诉我!
*/ public class DesPKCS7Encrypter { 
Cipher ecipher; Cipher dcipher; DesPKCS7Encrypter(byte[] keyBytes, byte[] ivBytes) throws Exception
{
Init(keyBytes,ivBytes);
} DesPKCS7Encrypter(DESKeySpec keySpec, IvParameterSpec ivSpec) throws Exception { Init(keySpec,ivSpec); } private void Init(byte[] keyBytes, byte[] ivBytes) throws Exception { DESKeySpec dks = new DESKeySpec(keyBytes); SecretKeyFactory keyFactory = SecretKeyFactory.getInstance( "DES" ); SecretKey key = keyFactory.generateSecret( dks ); IvParameterSpec iv = new IvParameterSpec(ivBytes); Init(key,iv); } private void Init(DESKeySpec keySpec, IvParameterSpec iv) throws Exception { SecretKeyFactory keyFactory = SecretKeyFactory.getInstance( "DES" ); SecretKey key = keyFactory.generateSecret( keySpec ); Init(key,iv); } private void Init(SecretKey key, IvParameterSpec iv) throws Exception { AlgorithmParameterSpec paramSpec = iv; try { ecipher = Cipher.getInstance("DES/CBC/NoPadding"); dcipher = Cipher.getInstance("DES/CBC/NoPadding"); // CBC requires an initialization vector ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec); dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec); } catch (Exception e) { throw e; } } public void encrypt(InputStream in, OutputStream out) { try { // Bytes written to out will be encrypted out = new CipherOutputStream(out, ecipher); byte[] buf = new byte[this.ecipher.getBlockSize()]; // Read in the cleartext bytes and write to out to encrypt int numRead = 0; while (true) { numRead = in.read(buf); boolean bBreak = false; if(numRead == -1 || numRead < buf.length) { int pos = numRead == -1? 0:numRead; byte byteFill = (byte)(buf.length - pos); for(int i = pos;i<buf.length; ++i) { buf[i] = byteFill; } bBreak = true; } out.write(buf); if(bBreak) break; } out.close(); } catch (java.io.IOException e) { System.out.println("Exception e in encrypt="+e); } } public void decrypt(InputStream in, OutputStream out) { try { // Bytes read from in will be decrypted in = new CipherInputStream(in, dcipher); byte[] buf = new byte[this.dcipher.getBlockSize()]; // Read in the decrypted bytes and write the cleartext to out int numRead = 0; while ((numRead = in.read(buf)) >= 0) { if(in.available() > 0) { out.write(buf, 0, numRead); } else { byte byteBlock = buf[buf.length -1]; int i = 0; for(i = buf.length - byteBlock; i >= 0 && i < buf.length; ++i) { if(buf[i] != byteBlock) { break; } } if(i == buf.length) { out.write(buf,0,buf.length - byteBlock); } else { out.write(buf); } } } out.close(); } catch (java.io.IOException e) { System.out.println("Exception e in decrypt="+e); } } public static void main(String args[]) { try { // 生成Key和IV byte[] byteKey = new byte[8]; //"12345678".getBytes("ASCII"); byte[] byteIv = new byte[8]; //"98765432".getBytes("ASCII"); FileInputStream fisKey = new FileInputStream("key.dat"); FileInputStream fisIv = new FileInputStream("iv.dat"); fisKey.read(byteKey); fisIv.read(byteIv); fisKey.close(); fisIv.close(); // 创建加密实例 DesPKCS7Encrypter encrypter = new DesPKCS7Encrypter(byteKey,byteIv); // 生成要加密的数据 String strData = "ni hao"; System.out.println(strData); ByteArrayInputStream bais = new ByteArrayInputStream(strData.getBytes("utf-8")); // 声明加密输出 ByteArrayOutputStream baos = new ByteArrayOutputStream(); // Base64 加密实例 BASE64Encoder base64Encoder = new BASE64Encoder(); //加密 encrypter.encrypt(bais,baos); //Base64加密 String outStr = base64Encoder.encode(baos.toByteArray()); //结果 System.out.println(outStr); // 初始化解密数据 bais = new ByteArrayInputStream(baos.toByteArray()); // 声明解密输出 baos = new ByteArrayOutputStream(); // 解密 encrypter.decrypt(bais,baos); //查看解密结果 System.out.println(baos.toString("utf-8")); } catch (Exception e) { System.out.println("Exception e="+e); } } } 也许还有更好的方法，也许Java已经有了该方法。还请高手告诉我呀。