Java AES暗号解読の簡単な実現方法

package com.mstf.aes;
 
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
 
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;
 
/**
 * AES    
 * @author ceet
 *
 */
public class AESUntil {
 /**
  *   
  *
  *
  */
 public static String Ecodes(String content, String key) {
  if (content == null || content.length() < 1)
   return null;
 
  try {
   KeyGenerator kgen = KeyGenerator.getInstance("AES");
   kgen.init(128, new SecureRandom(key.getBytes()));
   SecretKey secretKey = kgen.generateKey();
   byte[] enCodeFormat = secretKey.getEncoded();
   SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, "AES");
   Cipher cipher = Cipher.getInstance("AES");
   byte[] byteContent = content.getBytes("utf-8");
   cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
   byte[] byteRresult = cipher.doFinal(byteContent);
   StringBuffer sb = new StringBuffer();
   for (int i = 0; i < byteRresult.length; i++) {
    String hex = Integer.toHexString(byteRresult[i] & 0xFF);
    if (hex.length() == 1) {
     hex = '0' + hex;
    }
    sb.append(hex.toUpperCase());
   }
   return sb.toString();
  } 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;
 }
 
 /**
  *   
  *
  *
  */
 public static String Dcodes(String content, String key) {
  if (content == null || content.length() < 1)
   return null;
 
  if (content.trim().length() < 19)
   return content;
 
  byte[] byteRresult = new byte[content.length() / 2];
  for (int i = 0; i < content.length() / 2; i++) {
   int high = Integer.parseInt(content.substring(i * 2, i * 2 + 1), 16);
   int low = Integer.parseInt(content.substring(i * 2 + 1, i * 2 + 2), 16);
   byteRresult[i] = (byte) (high * 16 + low);
  }
  try {
   KeyGenerator kgen = KeyGenerator.getInstance("AES");
   kgen.init(128, new SecureRandom(key.getBytes()));
   SecretKey secretKey = kgen.generateKey();
   byte[] enCodeFormat = secretKey.getEncoded();
   SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, "AES");
   Cipher cipher = Cipher.getInstance("AES");
   cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
   byte[] result = cipher.doFinal(byteRresult);
   return new String(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;
 }
 
 /**
  *     
  * 【ceet      】
  * 【admin         】
  * 【67BE5ED967DBA9B9810C295BE6DEF5D5        】
  * 【    ceet，  67BE5ED967DBA9B9810C295BE6DEF5D5        】
  * @param args
  */
 //     
 public static void main(String[] args) {
  System.out.println("       ："+Ecodes("admin", "ceet"));
  System.out.println("       ："+Dcodes("67BE5ED967DBA9B9810C295BE6DEF5D5", "ceet"));
 }
}