package com.ruoyi.utils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;
import java.util.Base64;

/**
 * 注意：DES加密和解密过程中，密钥长度都必须是8的倍数
 */
public class DESUtil {
    public DESUtil() {
    }

    // 测试
    public static void main(String args[]) {
        // 待加密内容
        String str = "我是司军冠";
        // 密码，长度要是8的倍数
        String password = "xxxltk00";

        byte[] result = DESUtil.encrypt(str.getBytes(), password);
        // System.out.println("加密后：----" + new String(result));
        System.out.println("加密后：----" + byteToHex(result));
        // 直接将如上内容解密
        try {
            byte[] decryResult = DESUtil.decrypt(result, password);
            System.out.println("解密后：----" + new String(decryResult));
        } catch (Exception e1) {
            e1.printStackTrace();
        }
    }

    /**
     * 加密
     *
     * @param datasource byte[]
     * @param password   String
     * @return byte[]
     */
    public static byte[] encrypt(byte[] datasource, String password) {
        try {
            SecureRandom random = new SecureRandom();
            DESKeySpec desKey = new DESKeySpec(password.getBytes());
            // 创建一个密匙工厂，然后用它把DESKeySpec转换成
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey securekey = keyFactory.generateSecret(desKey);
            // Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
            // 现在，获取数据并加密
            // 正式执行加密操作
            return cipher.doFinal(addZero(datasource));
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param src      byte[]
     * @param password String
     * @return byte[]
     * @throws Exception
     */
    public static byte[] decrypt(byte[] src, String password) throws Exception {
        // DES算法要求有一个可信任的随机数源
        SecureRandom random = new SecureRandom();
        // 创建一个DESKeySpec对象
        DESKeySpec desKey = new DESKeySpec((password.getBytes()));
        // 创建一个密匙工厂
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        // 将DESKeySpec对象转换成SecretKey对象
        SecretKey securekey = keyFactory.generateSecret(desKey);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
        // 用密匙初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, random);
        // 真正开始解密操作
        return cipher.doFinal(src);
    }

    public static byte[] getKey(byte[] keyRule) {
        SecretKeySpec key = null;
        byte[] keyByte = keyRule;
        System.out.println(keyByte.length);
        // 创建一个空的八位数组,默认情况下为0
        byte[] byteTemp = new byte[8];
        // 将用户指定的规则转换成八位数组
        int i = 0;
        for (; i < byteTemp.length && i < keyByte.length; i++) {
            byteTemp[i] = keyByte[i];
        }
        key = new SecretKeySpec(byteTemp, "DES");
        return key.getEncoded();
    }

    public static byte[] addZero(byte[] data) {
        byte[] dataByte = data;

        if (data.length % 8 != 0) {
            byte[] temp = new byte[8 - data.length % 8];
            dataByte = byteMerger(data, temp);
        }
        return dataByte;
    }

    // java 合并两个byte数组
    // System.arraycopy()方法
    public static byte[] byteMerger(byte[] bt1, byte[] bt2) {
        byte[] bt3 = new byte[bt1.length + bt2.length];
        System.arraycopy(bt1, 0, bt3, 0, bt1.length);
        System.arraycopy(bt2, 0, bt3, bt1.length, bt2.length);
        return bt3;
    }

    /**
     * byte数组转hex
     * @param bytes
     * @return
     */
    public static String byteToHex(byte[] bytes){
        String base64Str = Base64.getEncoder().encodeToString(bytes);
        return base64Str;
    }

}