package com.albedo.security;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.security.Key;
import java.security.SecureRandom;
import java.util.Base64;

 
/**
 * des 加解密實現
 */
public class DES3Util {
    //字元編碼
    public static final String CHARSET_UTF8 = "UTF-8";
    //加密演算法DES
    public static final String DES3 = "desede";
    //電話本模式
    public static final String DES3_ECB = "DESEDE/ECB/PKCS5Padding";
    //加密塊鏈模式--推薦
    public static final String DES3_CBC = "DESEDE/CBC/PKCS5Padding";


    
 
/**
     * 生成key
     *
     * @param password
     * @return
     * @throws Exception
     */
    private static Key generateKey(String password) throws Exception {
        //由於DES3密碼不能小於24位，因此，任意長度密碼經過Md5轉化後，變為定長32位執行加解密處理
        DESedeKeySpec dks = new DESedeKeySpec(Md5Utils.encrypt(password).getBytes(CHARSET_UTF8));
        SecretKeyFactory keyFactory 
 
= SecretKeyFactory.getInstance(DES3);
        return keyFactory.generateSecret(dks);
    }

    /**
     * 3DES加密字串--ECB格式
     *
     * @param password 加密密碼，長度不能夠小於8位
     * @param data     待加密字串
     * @return 加密後內容
     */
    public static String encryptECB(String password, String data) throws Exception{
            Key secretKey = generateKey(password);
            Cipher cipher = Cipher.getInstance(DES3_ECB);
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, new SecureRandom());
            byte[] bytes = cipher.doFinal(data.getBytes(CHARSET_UTF8));
            //JDK1.8及以上可直接使用Base64，JDK1.7及以下可以使用BASE64Encoder
            return new String(Base64.getEncoder().encode(bytes));

    }

    /**
     * 3DES解密字串--ECB格式
     *
     * @param password 解密密碼，長度不能夠小於8位
     * @param data     待解密字串
     * @return 解密後內容
     */
    public static String decryptECB(String password, String data) throws Exception {

        Key secretKey = generateKey(password);
        Cipher cipher = Cipher.getInstance(DES3_ECB);
        cipher.init(Cipher.DECRYPT_MODE, secretKey, new SecureRandom());
        return new String(cipher.doFinal(Base64.getDecoder().decode(data.getBytes(CHARSET_UTF8))), CHARSET_UTF8);

    }
    /**
     * 3DES加密字串-CBC加密格式
     *
     * @param password 加密密碼，長度不能夠小於8位
     * @param data     待加密字串
     * @return 加密後內容
     */
    public static String encryptCBC(String password, String data) throws Exception{
            Key secretKey = generateKey(password);
            Cipher cipher = Cipher.getInstance(DES3_CBC);
            IvParameterSpec spec=new IvParameterSpec("12345678".getBytes(CHARSET_UTF8));
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, spec);
            byte[] bytes = cipher.doFinal(data.getBytes(CHARSET_UTF8));
            //JDK1.8及以上可直接使用Base64，JDK1.7及以下可以使用BASE64Encoder
            return new String(Base64.getEncoder().encode(bytes));

    }

    /**
     * 3DES解密字串--CBC格式
     *
     * @param password 解密密碼，長度不能夠小於8位
     * @param data     待解密字串
     * @return 解密後內容
     */
    public static String decryptCBC(String password, String data) throws Exception {
        Key secretKey = generateKey(password);
        Cipher cipher = Cipher.getInstance(DES3_CBC);
        IvParameterSpec spec=new IvParameterSpec("12345679".getBytes(CHARSET_UTF8));
        cipher.init(Cipher.DECRYPT_MODE, secretKey, spec);
        return new String(cipher.doFinal(Base64.getDecoder().decode(data.getBytes(CHARSET_UTF8))), CHARSET_UTF8);

    }


}