1// Aim: Program to perform Digital Signature Standard (Digital Signature Standard).
2import java.security.*;
3import java.util.*;
4public class ds {
5    public static void main(String[] args) throws Exception{
6        KeyPairGenerator keygen = KeyPairGenerator.getInstance("DSA");
7        keygen.initialize(2048);
8        KeyPair kk = keygen.generateKeyPair();
9        PrivateKey priv = kk.getPrivate();
10        PublicKey pub = kk.getPublic();
11
12        Scanner sc = new Scanner(System.in);
13        System.out.print("enter the text :");
14        String text = sc.nextLine();
15
16        Signature sig = Signature.getInstance("SHA256withDSA");
17        sig.initSign(priv);
18        sig.update(text.getBytes());
19        byte[] digital = sig.sign();
20        System.out.println("digital signature : "+Base64.getEncoder().encodeToString(digital));
21
22        sig.initVerify(pub);
23        sig.update(text.getBytes());
24        boolean isVerified = sig.verify(digital);
25        System.out.println("signature verified : "+isVerified);
26    }
27}
28