Digital signature sample code (JAVA)

Sample program

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *Sample for signature and signature verification with ECDSA 160bit
 */
public class ECDSASignature {

    public static void main(String argv[]){
        signatureTest();
    }
    
    public static void signatureTest(){

        /**
         *Issue key pair
         */
        KeyPairGenerator keyPairGenerator = null;
        try {
            keyPairGenerator = KeyPairGenerator.getInstance("EC");
        } catch (NoSuchAlgorithmException ex) {
            return;
        }
        SecureRandom secureRandom = new SecureRandom();
        keyPairGenerator.initialize(160, secureRandom);
        KeyPair pair = keyPairGenerator.generateKeyPair();
        Key publicKey = pair.getPublic();
        Key privateKey = pair.getPrivate();        
        
        //For the time being, just a string
        String hako = "Qiita is a technical information sharing service for programmers.";
        
        /**
         *Sign with private key (ECDSA 160bit)
         */
        byte[] sign = null;
        try {
            Signature signatureSign = null;
            signatureSign = Signature.getInstance("NONEwithECDSA");
            signatureSign.initSign((PrivateKey)privateKey, secureRandom);
            signatureSign.update(hako.getBytes());
            sign = signatureSign.sign();
            
            System.out.println("sign: " + new String(sign));

        } catch (InvalidKeyException | NoSuchAlgorithmException | SignatureException ex) {
            Logger.getLogger(ECDSASignature.class.getName()).log(Level.SEVERE, null, ex);
        }
        
        /**
         *Verify signature with public key
         */
        Signature signatureVerify = null;
        try {
            signatureVerify = Signature.getInstance("NONEwithECDSA");
            signatureVerify.initVerify((PublicKey)publicKey);
            signatureVerify.update(hako.getBytes());
            boolean verifyResult = signatureVerify.verify(sign);
            System.out.println(verifyResult ? "Signature OK" : "Signature NG");
            
        } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
            Logger.getLogger(ECDSASignature.class.getName()).log(Level.SEVERE, null, e);
        }
        
    }

}

Execution result

sign:(Omitted)
Signature OK