package demo.security;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.Scanner;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

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

/*
 * AES對(duì)稱加密和解密
 */
public class SymmetricEncoder {
 /*
  * 加密
  * 1.構(gòu)造密鑰生成器
  * 2.根據(jù)ecnodeRules規(guī)則初始化密鑰生成器
  * 3.產(chǎn)生密鑰
  * 4.創(chuàng)建和初始化密碼器
  * 5.內(nèi)容加密
  * 6.返回字符串
  */
  public static String AESEncode(String encodeRules,String content){
    try {
      //1.構(gòu)造密鑰生成器，指定為AES算法,不區(qū)分大小寫
      KeyGenerator keygen=KeyGenerator.getInstance("AES");
      //2.根據(jù)ecnodeRules規(guī)則初始化密鑰生成器
      //生成一個(gè)128位的隨機(jī)源,根據(jù)傳入的字節(jié)數(shù)組
      keygen.init(128, new SecureRandom(encodeRules.getBytes()));
       //3.產(chǎn)生原始對(duì)稱密鑰
      SecretKey original_key=keygen.generateKey();
       //4.獲得原始對(duì)稱密鑰的字節(jié)數(shù)組
      byte [] raw=original_key.getEncoded();
      //5.根據(jù)字節(jié)數(shù)組生成AES密鑰
      SecretKey key=new SecretKeySpec(raw, "AES");
       //6.根據(jù)指定算法AES自成密碼器
      Cipher cipher=Cipher.getInstance("AES");
       //7.初始化密碼器，第一個(gè)參數(shù)為加密(Encrypt_mode)或者解密解密(Decrypt_mode)操作，第二個(gè)參數(shù)為使用的KEY
      cipher.init(Cipher.ENCRYPT_MODE, key);
      //8.獲取加密內(nèi)容的字節(jié)數(shù)組(這里要設(shè)置為utf-8)不然內(nèi)容中如果有中文和英文混合中文就會(huì)解密為亂碼
      byte [] byte_encode=content.getBytes("utf-8");
      //9.根據(jù)密碼器的初始化方式--加密：將數(shù)據(jù)加密
      byte [] byte_AES=cipher.doFinal(byte_encode);
     //10.將加密后的數(shù)據(jù)轉(zhuǎn)換為字符串
      //這里用Base64Encoder中會(huì)找不到包
      //解決辦法：
      //在項(xiàng)目的Build path中先移除JRE System Library，再添加庫JRE System Library，重新編譯后就一切正常了。
      String AES_encode=new String(new BASE64Encoder().encode(byte_AES));
     //11.將字符串返回
      return AES_encode;
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    } catch (InvalidKeyException e) {
      e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
    } catch (BadPaddingException e) {
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    }
    
    //如果有錯(cuò)就返加nulll
    return null;     
  }
  /*
   * 解密
   * 解密過程：
   * 1.同加密1-4步
   * 2.將加密后的字符串反紡成byte[]數(shù)組
   * 3.將加密內(nèi)容解密
   */
  public static String AESDncode(String encodeRules,String content){
    try {
      //1.構(gòu)造密鑰生成器，指定為AES算法,不區(qū)分大小寫
      KeyGenerator keygen=KeyGenerator.getInstance("AES");
      //2.根據(jù)ecnodeRules規(guī)則初始化密鑰生成器
      //生成一個(gè)128位的隨機(jī)源,根據(jù)傳入的字節(jié)數(shù)組
      keygen.init(128, new SecureRandom(encodeRules.getBytes()));
       //3.產(chǎn)生原始對(duì)稱密鑰
      SecretKey original_key=keygen.generateKey();
       //4.獲得原始對(duì)稱密鑰的字節(jié)數(shù)組
      byte [] raw=original_key.getEncoded();
      //5.根據(jù)字節(jié)數(shù)組生成AES密鑰
      SecretKey key=new SecretKeySpec(raw, "AES");
       //6.根據(jù)指定算法AES自成密碼器
      Cipher cipher=Cipher.getInstance("AES");
       //7.初始化密碼器，第一個(gè)參數(shù)為加密(Encrypt_mode)或者解密(Decrypt_mode)操作，第二個(gè)參數(shù)為使用的KEY
      cipher.init(Cipher.DECRYPT_MODE, key);
      //8.將加密并編碼后的內(nèi)容解碼成字節(jié)數(shù)組
      byte [] byte_content= new BASE64Decoder().decodeBuffer(content);
      /*
       * 解密
       */
      byte [] byte_decode=cipher.doFinal(byte_content);
      String AES_decode=new String(byte_decode,"utf-8");
      return AES_decode;
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    } catch (InvalidKeyException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
    } catch (BadPaddingException e) {
      e.printStackTrace();
    }
    
    //如果有錯(cuò)就返加nulll
    return null;     
  }
  
  public static void main(String[] args) {
    SymmetricEncoder se=new SymmetricEncoder();
    Scanner scanner=new Scanner(System.in);
    /*
     * 加密
     */
    System.out.println("使用AES對(duì)稱加密，請(qǐng)輸入加密的規(guī)則");
    String encodeRules=scanner.next();
    System.out.println("請(qǐng)輸入要加密的內(nèi)容:");
    String content = scanner.next();
    System.out.println("根據(jù)輸入的規(guī)則"+encodeRules+"加密后的密文是:"+se.AESEncode(encodeRules, content));
    
    /*
     * 解密
     */
    System.out.println("使用AES對(duì)稱解密，請(qǐng)輸入加密的規(guī)則：(須與加密相同)");
     encodeRules=scanner.next();
    System.out.println("請(qǐng)輸入要解密的內(nèi)容（密文）:");
     content = scanner.next();
    System.out.println("根據(jù)輸入的規(guī)則"+encodeRules+"解密后的明文是:"+se.AESDncode(encodeRules, content));
  }

}