import java.security.SecureRandom;

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

public class DesUtil {
    private final static String DES = "DES";

    public static final String CLUB_KEY = "47poksdfj2";

    public 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();
        //從原始金鑰資料建立DESKeySpec物件
        DESKeySpec dks = new DESKeySpec(key);
        //建立一個金鑰工廠，然後用他把DESKeySpec轉換成SecretKey物件
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
 
        // Cipher物件實際完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 用金鑰初始化Cipher物件
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
        byte[] arrB = cipher.doFinal(data);
        int iLen = arrB.length;
        // 每個byte用兩個字元才能表示，所以字串的長度是陣列長度的兩倍
        StringBuffer sb = new StringBuffer(iLen * 2);
 
        for (int i = 0; i < iLen; i++) {
            int intTmp = arrB[i];
            // 把負數轉換為正數
            while (intTmp < 0) {
                intTmp = intTmp + 256;
            }
            // 小於0F的數需要在前面補0
            if (intTmp < 16) {
                sb.append("0");
            }
            sb.append(Integer.toString(intTmp, 16));
        }
        return sb.toString().getBytes();
    }
    /**
     * 根據鍵值進行加密
     * @param data
     * @param key  加密鍵byte陣列
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key) throws Exception {
        byte[] bt = encrypt(data.getBytes(), key.getBytes());
        return new String(bt,"utf-8");
    }
    /**
     * Description 根據鍵值進行解密
     * @param data
     * @param key  加密鍵byte陣列
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] arrB, byte[] key) throws Exception {
        int iLen = arrB.length;
        // 兩個字元表示一個位元組，所以位元組陣列長度是字串長度除以2
        byte[] arrOut = new byte[iLen / 2];
        for (int i = 0; i < iLen; i = i + 2) {
            String strTmp = new String(arrB, i, 2);
            try {
                arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
            } catch (Exception e) {
            }
        }
        // 生成一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();
        // 從原始金鑰資料建立DESKeySpec物件
        DESKeySpec dks = new DESKeySpec(key);

        // 建立一個金鑰工廠，然後用它把DESKeySpec轉換成SecretKey物件
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher物件實際完成解密操作
        Cipher cipher = Cipher.getInstance("DES");
        // 用金鑰初始化Cipher物件
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
        return cipher.doFinal(arrOut);
    }


    /**
     * 根據鍵值進行解密
     * @param data
     * @param key  加密鍵byte陣列
     * @return
     * @throws Exception
     */
    public static String decrypt(String data, String key) throws Exception {
        if (data == null) {
            return null;
        }
        byte[] buf = data.getBytes("utf-8");
        //byte[] buf = Base64Binrary.decodeBase64Binrary(data);
        byte[] bt = decrypt(buf,key.getBytes());
        return new String(bt,"utf-8");
    }