java加密解密详解

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;

/**
 *
 * 作者: IT一号男
 * 功能:安全密钥类(进行加密解密)
 * 时间:2012-10-20 下午11:06:16
 * 备注:1.加密分为对称加密（加密解密的密钥必须相同,只有通信的上方才能知道密钥.速度快）；
 *     2.非对称加密(即公钥加密,速度慢，加密解密的密钥不同，只有一个知道私钥，任何人都可以知道公钥)；
 *
 */

public class SecurityKey {

 /**
  * 加密
  *
  * @param encryptFile
  *            加密文件
  * @throws NoSuchAlgorithmException
  * @throws NoSuchPaddingException
  * @throws InvalidKeyException
  * @throws IllegalBlockSizeException
  * @throws BadPaddingException
  * @throws FileNotFoundException
  * @throws IOException
  * @throws Exception
  */
 private static void secretEncrypt(String encryptFile)
   throws NoSuchAlgorithmException, NoSuchPaddingException,
   InvalidKeyException, IllegalBlockSizeException,
   BadPaddingException, FileNotFoundException, IOException, Exception {
  // 加密
  Cipher cipher = Cipher.getInstance("AES");// 根据加密算法创建加密对象
  SecretKey key = KeyGenerator.getInstance("AES").generateKey();
  cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化加密方式
  byte[] results = cipher.doFinal(encryptFile.getBytes());
  System.out.println(new String(results));

  // 创建解密key
  FileOutputStream foskey = new FileOutputStream("zxx_secret.key");
  ObjectOutputStream ossSecretKey = new ObjectOutputStream(foskey);
  ossSecretKey.writeObject(key);
  ossSecretKey.close();
  foskey.close();
      
 /*SecretKey key2=SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(new PBEKeySpec("12345678".toCharArray()));
 cipher.init(Cipher.DECRYPT_MODE,key2);*/
 // 存放解密数据
  FileOutputStream fosData = new FileOutputStream("zxx.dat");
  fosData.write(results);
  fosData.close();

 }

 /**
  * 解密
  *
  * @throws Exception
  */
 private static void secretDecrypt() throws Exception {

  Cipher cipher = Cipher.getInstance("AES");// 根据加密算法创建加密对象
  FileInputStream fisKey = new FileInputStream("zxx_secret.key");
  ObjectInputStream oisKey = new ObjectInputStream(fisKey);
  Key key = (Key) oisKey.readObject();// 从文件读取密钥
  cipher.init(Cipher.DECRYPT_MODE, key);

  FileInputStream fisData = new FileInputStream("zxx.dat");
  byte[] src = new byte[fisData.available()];
  int len = fisData.read(src);
  int total = 0;
  while (total <= src.length) {
   total += len;
   len = fisData.read(src, total, src.length - total);
  }
  byte[] result = cipher.doFinal(src);
     oisKey.close();
  fisData.close();

  System.out.println("解密内容为:" + new String(result));

 }

 public static void main(String[] args) throws Exception {
  //secretEncrypt("pp");// 加密
  secretDecrypt();// 解密
 }

}