Java encryption and decryption function example based on AES symmetric encryption algorithm

The example in this article describes the encryption and decryption functions implemented by java based on the AES symmetric encryption algorithm. Share it with everyone for your reference, the details are as follows:

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 {
      // 使用静态代码块来生成KeyGenerator对象
      //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对象实际完成加密操作
      Cipher cipher = Cipher.getInstance(AES);
      // 加密内容进行编码
      byte[] byteContent = content.getBytes(UTF8);
      // 用密匙初始化Cipher对象
      cipher.init(Cipher.ENCRYPT_MODE, key);
      // 正式执行加密操作
      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 {// 使用静态代码块来生成KeyGenerator对象
      //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对象实际完成加密操作
      Cipher cipher = Cipher.getInstance(AES);
      // 用密匙初始化Cipher对象
      cipher.init(Cipher.DECRYPT_MODE, key);
      // 正式执行解密操作
      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;
  }
  /**
   * 二进制--》十六进制转化
   * @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 = &#39;0&#39; + hex;
      }
      sb.append(hex.toUpperCase());
    }
    return sb.toString();
  }
  /**
   * 十六进制--》二进制转化
   * @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加密测试";
    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);
    // 解密内容进行解码
    String result = new String(decryptResult, UTF8);
    System.out.println("解密后：" + result);
    long end= new Date().getTime();
    System.out.println(end-begin);
  }
}

Note: SecureRandom generates a secure random number sequence, password.getBytes() is the seed, as long as the seed is the same, the sequence will be the same, so decryption only requires a password. This sequence can be restored.

I hope this article will be helpful to everyone in java programming.

For more java encryption and decryption function examples based on the AES symmetric encryption algorithm, please pay attention to the PHP Chinese website!