Java密码学验证签名

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.PrivateKey;

import java.security.Signature;



public class SignatureVerification {

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



      //Creating KeyPair generator object

      KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("DSA");



      //Initializing the key pair generator

      keyPairGen.initialize(2048);



      //Generate the pair of keys

      KeyPair pair = keyPairGen.generateKeyPair();



      //Getting the privatekey from the key pair

      PrivateKey privKey = pair.getPrivate();



      //Creating a Signature object

      Signature sign = Signature.getInstance("SHA256withDSA");



      //Initializing the signature

      sign.initSign(privKey);



      byte[] bytes = "Hello how are you".getBytes();

      //Adding data to the signature

      sign.update(bytes);



      //Calculating the signature

      byte[] signature = sign.sign();      



      //Initializing the signature

      sign.initVerify(pair.getPublic());

      sign.update(bytes);



      //Verifying the signature

      boolean bool = sign.verify(signature);



      if(bool) {

         System.out.println("Signature verified");   

      }else{

         System.out.println("Signature failed");

      }

   }

}