Java uses Hex encoding and decoding to implement Aes encryption and decryption function examples

The example of this article describes how Java uses Hex encoding and decoding to implement Aes encryption and decryption functions. Share it with everyone for your reference, the details are as follows:

The Aes encryption and decryption method here is encoded and decoded using Hex

package com.baidu.wallet.bdwallet.utils;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
public class Test {
   private static final String AES="AES";
   private static final String UTF8="UTF-8";
    /**
    * AES加密
    * @param content
    * @param pkey
    * @return
    * @throws DecoderException
    */
    private static byte[] encrypt(String content, String pkey) throws DecoderException {
      try {
        String private_key=pkey;
        byte[] encodeFormat=null;
        try {
          //秘钥 Hex解码为什么秘钥要进行解码，因为秘钥是某个秘钥明文进行了Hex编码后的值，所以在使用的时候要进行解码
          encodeFormat = Hex.decodeHex(private_key.toCharArray());
        } catch (DecoderException e) {
          e.printStackTrace();
        }
        SecretKeySpec key = new SecretKeySpec(encodeFormat, AES);
        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        // 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;
    }
    /**
     * AES解密
     * @param contents
     * @param password
     * @return
     * @throws DecoderException
     */
    private static byte[] decrypt(String contents, String password) throws DecoderException {
      try {
        //密文使用Hex解码
        byte[]content = Hex.decodeHex(contents.toCharArray());
        //秘钥 Hex解码为什么秘钥要进行解码，因为秘钥是某个秘钥明文进行了Hex编码后的值，所以在使用的时候要进行解码
        byte[] encodeFormat = Hex.decodeHex(password.toCharArray());
        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;
    }
    /**
     * Aes加密
     * @param context 明文
     * @param private_key 秘钥
     * @return
     * @throws DecoderException
     */
    public static String encryption(String context,String private_key) throws DecoderException{
      //加密后的明文也就变成了密文
      byte[] encryptResult = encrypt(context, private_key);
      //密码文Hex编码
      String encryptResultStr = Hex.encodeHexString(encryptResult);
      return encryptResultStr;
    }
    /**
    * Aes解密
    * @param context 密文
    * @param private_key 秘钥
    * @return
    * @throws DecoderException
    * @throws UnsupportedEncodingException
    */
    public static String decryption(String context,String private_key) throws DecoderException, UnsupportedEncodingException{
     //这里的密文解密前先进行了Hex解码
      byte[] decryptResult = decrypt(context, private_key);
      String result = new String(decryptResult, UTF8);
      return result;
    }
    public static void main(String[] args) throws UnsupportedEncodingException, DecoderException {
      //加密内容
      String content = "123456787654321";
      //AES加密解密秘钥
      String password = "这个值一般都是给定的，双发都知道";
      // 加密
      System.out.println("加密前：" + content);
      // 调用加密方法
      String encryptResultStr = encryption(content, password);
      System.out.println("加密后：" + encryptResultStr);
      // 调用解密方法
      String result = decryption(encryptResultStr, password);
      // 解密内容进行解码
      System.out.println("解密后：" + result);
    }
}

This method has been used in formal projects and there is no problem. Please note You have to correct the AES encryption and decryption here...

The method used above is the org.apache.commons.codec.binary.Hex class. The configuration in maven is as follows:

<dependency>
  <groupId>commons-codec</groupId>
  <artifactId>commons-codec</artifactId>
  <version>1.4</version>
</dependency>

Note: You need to use version 1.4 and above here. There should be no Hex.encodeHexString (byte[]) method for versions below 1.4!

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