/* TestECDSA -- Ensure ECDSA signatures are working.

   Copyright (C) 2016 Red Hat, Inc.

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU Affero General Public License as

published by the Free Software Foundation, either version 3 of the

License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License

along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

import java.math.BigInteger;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.Signature;

/**

 * @test

 */

public class TestECDSA {

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

        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");

        KeyPair key = keyGen.generateKeyPair();

        byte[] data = "This is a string to sign".getBytes("UTF-8");

        Signature dsa = Signature.getInstance("NONEwithECDSA");

        dsa.initSign(key.getPrivate());

        dsa.update(data);

        byte[] sig = dsa.sign();

        System.out.println("Signature: " + new BigInteger(1, sig).toString(16));

        Signature dsaCheck = Signature.getInstance("NONEwithECDSA");

        dsaCheck.initVerify(key.getPublic());

        dsaCheck.update(data);

        boolean success = dsaCheck.verify(sig);

        if (!success) {

            throw new RuntimeException("Test failed. Signature verification error");

        }

        System.out.println("Test passed.");

    }

}