JCA-HMAC

JCA的message digest介紹:
1.使用SHA-256產生HMAC

import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.Mac;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidKeyException;
import org.apache.commons.codec.binary.Base64;

/**
 * 
 * @author andy
 */
public class HmacExample {

    public static void main(String args[]) {
        try {
            KeyGenerator kg = KeyGenerator.getInstance("HmacSHA256");
            SecretKey sk = kg.generateKey();
        
            Mac mac = Mac.getInstance("HmacSHA256");//use HmacSHA256
            mac.init(sk);
            byte[] hmac = mac.doFinal("data".getBytes());
        
            String encodedString = new String( Base64.encodeBase64(hmac) );
      System.out.println("HMAC:"+encodedString);
  } catch (NoSuchAlgorithmException e1) {
         System.err.println(e1);
  } catch (InvalidKeyException e2) {
      System.err.println(e2);
  }
    }
 
}