package com.soufun.com;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Date;
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;
/**
 * @author WHD
 */
public class AesUtil {
  private static final String AES="AES";
  private static final String UTF8="UTF-8";
  static KeyGenerator kgen =null;
  static{
    try {
      kgen= KeyGenerator.getInstance(AES);
    } catch (NoSuchAlgorithmException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  /*
   * @param content:
   * @param password:
   */
  private static byte[] encrypt(String content, String password) {
    try {
      // 使用靜態(tài)代碼塊來生成KeyGenerator對象
      //KeyGenerator kgen = KeyGenerator.getInstance(AES);
      // 使用128 位
      kgen.init(128, new SecureRandom(password.getBytes()));
      SecretKey secretKey = kgen.generateKey();
      byte[] encodeFormat = secretKey.getEncoded();
      SecretKeySpec key = new SecretKeySpec(encodeFormat, AES);
      // Cipher對象實際完成加密操作
      Cipher cipher = Cipher.getInstance(AES);
      // 加密內容進行編碼
      byte[] byteContent = content.getBytes(UTF8);
      // 用密匙初始化Cipher對象
      cipher.init(Cipher.ENCRYPT_MODE, key);
      // 正式執(zhí)行加密操作
      byte[] result = cipher.doFinal(byteContent);
      return result;
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    } catch (InvalidKeyException e) {
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
      e.printStackTrace();
    } catch (BadPaddingException e) {
      e.printStackTrace();
    }
    return null;
  }
  /*
   * @param content:
   * @param password:
   */
  private static byte[] decrypt(byte[] content, String password) {
    try {// 使用靜態(tài)代碼塊來生成KeyGenerator對象
      //KeyGenerator kgen = KeyGenerator.getInstance(AES);
      // 使用128 位
      kgen.init(128, new SecureRandom(password.getBytes()));
      SecretKey secretKey = kgen.generateKey();
      byte[] encodeFormat = secretKey.getEncoded();
      SecretKeySpec key = new SecretKeySpec(encodeFormat, AES);
      // Cipher對象實際完成加密操作
      Cipher cipher = Cipher.getInstance(AES);
      // 用密匙初始化Cipher對象
      cipher.init(Cipher.DECRYPT_MODE, key);
      // 正式執(zhí)行解密操作
      byte[] result = cipher.doFinal(content);
      return result;
    } 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();
    }
    return null;
  }
  /**
   * 二進制--》十六進制轉化
   * @param buf
   * @return
   */
  private static String parseByte2HexStr(byte buf[]) {
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < buf.length; i++) {
      String hex = Integer.toHexString(buf[i] & 0xFF);
      if (hex.length() == 1) {
        hex = '0' + hex;
      }
      sb.append(hex.toUpperCase());
    }
    return sb.toString();
  }
  /**
   * 十六進制--》二進制轉化
   * @param hexStr
   * @return
   */
  private static byte[] parseHexStr2Byte(String hexStr) {
    if (hexStr.length() < 1) {
      return null;
    }
    byte[] result = new byte[hexStr.length() / 2];
    for (int i = 0; i < hexStr.length() / 2; i++) {
      int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
      int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
          16);
      result[i] = (byte) (high * 16 + low);
    }
    return result;
  }
  public static void main(String[] args) throws UnsupportedEncodingException {
    long begin=new Date().getTime();
    String content = "aaades加密測試";
    String password = "12345678dd";
    // 加密
    System.out.println("加密前：" + content);
    byte[] encryptResult = encrypt(content, password);
    String encryptResultStr = parseByte2HexStr(encryptResult);
    System.out.println("加密后：" + encryptResultStr);
    // 解密
    byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);
    byte[] decryptResult = decrypt(decryptFrom, password);
    // 解密內容進行解碼
    String result = new String(decryptResult, UTF8);
    System.out.println("解密后：" + result);
    long end= new Date().getTime();
    System.out.println(end-begin);
  }
}