java使用秘鑰 對字符串進行加密、解密

java使用秘鑰 對字符串進行加密、解密

package com.mybatis.plus.utils;

import java.io.IOException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 * DES加密 解密算法
 * @author zhangdi
 *
 */
public class DesUtil {

    private final static String DES = "DES";
    private final static String ENCODE = "GBK";
    private final static String defaultKey = "netwxactive";

    /**
     * 使用 默認key 加密
     * @param data 待加密數據
     * @return
     * @throws Exception
     */
    public static String encrypt(String data) throws Exception {
        byte[] bt = encrypt(data.getBytes(ENCODE), defaultKey.getBytes(ENCODE));
        String strs = new BASE64Encoder().encode(bt);
        return strs;
    }

    /**
     * 使用 默認key 解密
     * @param data 待解密數據
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data) throws IOException, Exception {
        if (data == null)
            return null;
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf, defaultKey.getBytes(ENCODE));
        return new String(bt, ENCODE);
    }

    /**
     * Description 根據鍵值進行加密
     * @param data 待加密數據
     * @param key 密鑰
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key) throws Exception {
        byte[] bt = encrypt(data.getBytes(ENCODE), key.getBytes(ENCODE));
        String strs = new BASE64Encoder().encode(bt);
        return strs;
    }

    /**
     * 根據鍵值進行解密
     * @param data 待解密數據
     * @param key    密鑰
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data, String key) throws IOException,
            Exception {
        if (data == null)
            return null;
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf, key.getBytes(ENCODE));
        return new String(bt, ENCODE);
    }

    /**
     * Description 根據鍵值進行加密
     * 
     * @param data
     * @param key
     *            加密鍵byte數組
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();
        // 從原始密鑰數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);
        // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher對象實際完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 用密鑰初始化Cipher對象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
        return cipher.doFinal(data);
    }

    /**
     * Description 根據鍵值進行解密
     * 
     * @param data
     * @param key 加密鍵byte數組
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();

        // 從原始密鑰數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);

        // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher對象實際完成解密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密鑰初始化Cipher對象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }
    
    public static void main(String[] args){
        String data = "我是需要被加密的數據";
        // 這里的key長度必須大於8位
        String key ="12345678";
        System.out.println("初始數據===>"+data);
        try {
            System.out.println();
            System.out.println(">>>>>>>>>>根據預定秘鑰加密后：" + encrypt(data, key));
            System.out.println(">>>>>>>>>>根據預定秘鑰解密后：" + decrypt(encrypt(data, key), key));

            System.out.println("==========================================");
            String encrypt = encrypt(data);
            System.out.println(">>>>>>>>>>默認秘鑰加密后："+encrypt);
            System.out.println(">>>>>>>>>>默認秘鑰解密后："+decrypt(encrypt));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
}