package com.stone.security;

import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

/**
 * PBE算法 对称加密 password-based encryption
 * @author stone
 * @date 2014-03-10 23:41:35
 */
public class PBE {
	static final String KEY_ALGORITHM = "PBEWithMD5AndDES";
//	static byte[] salt = "xiaoyang".getBytes(); // 盐：Salt must be 8 bytes long
	static byte[] salt = "哈皮aa".getBytes(); // 盐：Salt must be 8 bytes long  哈皮，在utf8中是6个字节
	static int iterationCount = 888; //循环次数
	static Cipher cipher;
	
	public static void main(String[] args) throws Exception {
		byte[] encrypt = encrypt("中华人民admin*&(*S&6");
		System.out.println("PBE加密后：" + Arrays.toString(encrypt));
		
		System.out.println("PBE解密后：" + decrypt(encrypt));
	}
	
	/**
	 * 使用PBE 算法 加密
	 * @return	加密后的字符数组
	 * @throws Exception
	 */
	static byte[] encrypt(String str) throws Exception {
		cipher = Cipher.getInstance(KEY_ALGORITHM);
		
		//使用SecretKeyFactory 生成key
		SecretKeyFactory factory = SecretKeyFactory.getInstance(KEY_ALGORITHM);
		PBEKeySpec keySpec = new PBEKeySpec("shizongyin".toCharArray());
		SecretKey key = factory.generateSecret(keySpec);
		System.out.println("key:" + Arrays.toString(key.getEncoded()));
		
		cipher.init(Cipher.ENCRYPT_MODE, key, new PBEParameterSpec(salt, iterationCount));//使用加密模式初始化 密钥
		return cipher.doFinal(str.getBytes()); //按单部分操作加密或解密数据，或者结束一个多部分操作。
	}
	
	/**
	 * 
	 * @param encrypt
	 * @return
	 * @throws Exception
	 */
	static String decrypt(byte[] encrypt) throws Exception {
		cipher = Cipher.getInstance(KEY_ALGORITHM);
		
		//使用SecretKeyFactory 生成key
		SecretKeyFactory factory = SecretKeyFactory.getInstance(KEY_ALGORITHM);
		PBEKeySpec keySpec = new PBEKeySpec("shizongyin".toCharArray());
		SecretKey key = factory.generateSecret(keySpec);
		System.out.println("key:" + Arrays.toString(key.getEncoded()));
		
		cipher.init(Cipher.DECRYPT_MODE, key, new PBEParameterSpec(salt, iterationCount));//使用加密模式初始化 密钥
		byte[] result = cipher.doFinal(encrypt); //按单部分操作加密或解密数据，或者结束一个多部分操作。
		
		return new String(result);
	}
	
}