Java Cryptography创建MAC

import java.security.Key;

import java.security.SecureRandom;



import javax.crypto.KeyGenerator;

import javax.crypto.Mac;



public class MacSample {

   public static void main(String args[]) throws Exception{



      //Creating a KeyGenerator object

      KeyGenerator keyGen = KeyGenerator.getInstance("DES");



      //Creating a SecureRandom object

      SecureRandom secRandom = new SecureRandom();



      //Initializing the KeyGenerator

      keyGen.init(secRandom);



      //Creating/Generating a key

      Key key = keyGen.generateKey();    



      //Creating a Mac object

      Mac mac = Mac.getInstance("HmacSHA256");



      //Initializing the Mac object

      mac.init(key);



      //Computing the Mac

      String msg = new String("Hi how are you");

      byte[] bytes = msg.getBytes();      

      byte[] macResult = mac.doFinal(bytes);



      System.out.println("Mac result:");

      System.out.println(new String(macResult));     

   }

}