KeyHelper.java

/* BEGIN LICENSE
  * Copyright © Blue Mind SAS, 2012-2017
  *
  * This file is part of BlueMind. BlueMind is a messaging and collaborative
  * solution.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of either the GNU Affero General Public License as
  * published by the Free Software Foundation (version 3 of the License).
  *
  * 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 LICENSE.txt
  * END LICENSE
  */
package net.bluemind.signature;

import static org.junit.Assert.assertTrue;

import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.SignatureException;
import java.util.Random;

import org.junit.Test;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;

public class KeysHelper {

	private PrivateKey priv;
	private PublicKey pub;

	public void setup() throws NoSuchAlgorithmException, NoSuchProviderException {
		KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA", "SUN");
		SecureRandom random = SecureRandom.getInstanceStrong();
		keyGen.initialize(1024, random);
		KeyPair pair = keyGen.generateKeyPair();
		this.priv = pair.getPrivate();
		this.pub = pair.getPublic();
	}

	public byte[] sign(byte[] data)
			throws InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException, SignatureException {
		Signature dsa = signature();
		dsa.initSign(priv);
		dsa.update(data);
		byte[] signed = dsa.sign();
		return signed;
	}

	private Signature signature() throws NoSuchAlgorithmException, NoSuchProviderException {
		return Signature.getInstance("SHA1withDSA", "SUN");
	}

	public boolean verify(byte[] data, byte[] signed)
			throws SignatureException, InvalidKeyException, NoSuchAlgorithmException, NoSuchProviderException {
		Signature sig = signature();
		sig.initVerify(pub);
		sig.update(data);
		return sig.verify(signed);
	}

	@Test
	public void testKeyHelper() throws Exception {
		Random rd = new Random();
		ByteBuf token = Unpooled.buffer();
		token.writeLong(rd.nextLong()).writeLong(rd.nextLong());
		String tokenHex = ByteBufUtil.hexDump(token);
		System.out.println("To sign: " + tokenHex);
		byte[] data = new byte[16];
		token.readBytes(data);
		KeysHelper kh = this;
		kh.setup();
		byte[] signature = kh.sign(data);
		ByteBuf sig = Unpooled.wrappedBuffer(signature);
		String sigHex = ByteBufUtil.hexDump(sig);
		System.out.println("Sig: " + sigHex);
		System.out.println("For the login page: " + tokenHex + ":" + sigHex);
		boolean verified = kh.verify(data, signature);
		assertTrue(verified);
	}

}