AES加密JAVA代码实现.doc

AES加密JAVA代码实现
2007年04月06日 星期五 15:11
package com.forms.struts.form;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class AES
{
     /**
      * Turns array of bytes into string
      *
      * @param buf
      *             Array of bytes to convert to hex string
      * @return Generated hex string
      */

private final static String algorithm = "AES";   

     private static String asHex(byte buf[])
     {
         StringBuffer strbuf = new StringBuffer(buf.length * 2);
         int i;

         for (i = 0; i < buf.length; i++)
         {
             if (((int) buf[i] & 0xff) < 0x10) strbuf.append("0");
             strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
         }
         return strbuf.toString();
     }

     private static byte[] asBin(String src){
      if(src.length()<1) return null;
      byte[] encrypted = new byte[src.length()/2];
      for(int i=0;i<src.length()/2;i++){
       int high = Integer.parseInt(src.substring(i * 2, i * 2 + 1 ), 16);
       int low = Integer.parseInt(src.substring(i * 2 + 1, i * 2 + 2), 16);

       encrypted[i] = (byte)(high * 16 + low);
      }
      return encrypted;
     }

     public static String getRawKey() {

      try{
          // Get the KeyGenerator
          KeyGenerator kgen = KeyGenerator.getInstance(algorithm);
          kgen.init(128); // 192 and 256 bits may not be available

          // Generate the secret key specs.
          SecretKey skey = kgen.generateKey();
          byte[] raw = skey.getEncoded();
          return asHex(raw);
      }catch (Exception e) {
          //App.log.info("AES", "获取密钥出错," + e.getMessage());
          return "";
   }        
     }

     public static String getEncrypt(String message, String rawKey){
      byte[] key = asBin(rawKey);
         // Instantiate the cipher
         try{   
          SecretKeySpec skeySpec = new SecretKeySpec(key, algorithm);

          Cipher cipher = Cipher.getInstance(algorithm);

          cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

          byte[] encrypted = cipher.doFinal(message.getBytes());

          return asHex(encrypted);
         }catch (Exception e) {
          //App.log.info("AES", "获取加密串出错," + e.getMessage());
          return "";
   }        
     }

     public static String getDecrypt(String encrypted, String rawKey){
      byte[] tmp = asBin(encrypted);
      byte[] key = asBin(rawKey);

      try{
       SecretKeySpec skeySpec = new SecretKeySpec(key, algorithm);

          Cipher cipher = Cipher.getInstance(algorithm);

          cipher.init(Cipher.DECRYPT_MODE, skeySpec);

          byte[] decrypted = cipher.doFinal(tmp);

          return new String(decrypted);
      }catch (Exception e) {
          //App.log.info("AES", "获取解密串出错," + e.getMessage());
          return "";
   }

     }

     public static void main(String[] args) throws Exception
     {
         String message = "带镜粉盒电费活动家jhdjf8748";

         String rawKey = getRawKey();   //得到钥匙
         System.out.println("Key = " + rawKey);

         String encrypted = getEncrypt(message,rawKey);
         System.out.println("org text = " + message);//原数据
         System.out.println("encrypted = " + encrypted);//加密以后

         String decrypted = getDecrypt(encrypted,rawKey);//解密串

         System.out.println("decrypted = " + decrypted);

     }
}