package com.hebabr.xy.exam.util;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.Random;

/**

• AES 加密方法，是對稱的密碼算法(加密與解密的密鑰一致)，這里使用最大的 256 位的密鑰
  /
  public class AESUtils3 {
  /*

  • 編碼格式
    /
    public static final String ENCODING = "utf-8";
    /*
  • 密鑰算法
    */
    private static final String KEY_ALGORITHM = "AES";
    private static String password = "dGVzdDp0ZXN0ABXC";

  //padding模式
  //NoPadding
  //PKCS5Padding
  //ISO10126Padding
  //PaddingMode.Zeros
  //PaddingMode.PKCS7
  public static String encryptCFB(String content, String key) {
  try {
  Cipher aesCFB = Cipher.getInstance("AES/CFB/NoPadding");
  SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(ENCODING), KEY_ALGORITHM);
  byte[] iv = key.getBytes(StandardCharsets.UTF_8);
  IvParameterSpec ivSpec = new IvParameterSpec(iv);
  aesCFB.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);
  byte[] contentBytes = content.getBytes();
  byte[] encryptBytes = aesCFB.doFinal(contentBytes);
  return Base64.getEncoder().encodeToString(encryptBytes);
  } catch (Exception ex) {
  ex.printStackTrace();
  }
  return null;
  }

  /***

  • @paramcontent 待解密內容，字符串形式

  • @paramkey 解密用的密鑰

  • @return 使用字符串形式返回解密內容

  • @throws Exception
    **/
    public static String decryptCFB(String content, String key) {
    try {
    Cipher aesCFB = Cipher.getInstance("AES/CFB/NoPadding");
    SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), KEY_ALGORITHM);
    byte[] decodeBytes = Base64.getMimeDecoder().decode(content);
    byte[] iv = key.getBytes(StandardCharsets.UTF_8);
    IvParameterSpec ivSpec = new IvParameterSpec(iv);
    aesCFB.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
    byte[] result = aesCFB.doFinal(decodeBytes);

     String AES_decode = new String(result, ENCODING);
     return AES_decode;
    

    } catch (Exception ex) {
    ex.printStackTrace();
    }
    return null;

  }

  public static void main(String[] args) throws Exception {
  String content = "{"token":"92b1f641-9311-4c46-984e-9d9debb2bc60","userId":1,"datetime":1682241938118}";
  System.out.println("需要加密的內容：" + content);

   String hexStr = encryptCFB(content, password);
   System.out.println("加密后:"+ hexStr);
  
   String decrypt = decryptCFB(hexStr, password);
   System.out.println("解密后的內容：" + decrypt);
  

  }

}