Use the power of threads!

GenerateVanityKey.java

/**
 * GenerateVanityKey.java – generates keypairs with a prefix
 * Copyright © 2014 David ‘Bombe’ Roden
 * <p>
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 * <p>
 * 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 General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 * <p>
 * GUID:1783028B-ECB6-462E-929E-A33A37D823BA
 */

package freenet.tools;

import static freenet.keys.InsertableClientSSK.createRandom;
import static java.lang.String.format;
import static java.lang.System.currentTimeMillis;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicLong;

import freenet.crypt.RandomSource;
import freenet.crypt.Yarrow;
import freenet.keys.FreenetURI;
import freenet.keys.InsertableClientSSK;

/**
 * Generates a vanity key pair, i.e. a keypair with the public key starting
 * with a specific set of characters.
 *
 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 */
public class GenerateVanityKey {

    public static void main(final String... arguments) throws Exception {
        if (arguments.length == 0) {
            System.err.println("Syntax: GenerateVanityKey <prefix> [<prefix> [...]]");
            System.exit(1);
        }
        System.err.println("*** You should not really be using this script!");
        System.err.println("*** If you manage to find a nice prefix for your site you make it easier");
        System.err.println("*** for an attacker to impersonate you: he only needs to find a key with");
        System.err.println("*** the same prefix because people are very lazy and won’t compare anthing");
        System.err.println("*** but the prefix!");
        final RandomSource randomSource = new Yarrow();
        long firstOutput = currentTimeMillis();
        long foundKeys = 0;
        AtomicLong generatedKeys = new AtomicLong();
        BlockingQueue<FreenetURI[]> resultKeypairs = new ArrayBlockingQueue<>(1);
        KeyMatcher keyMatcher = createKeyMatcher(arguments);
        Runnable keyFinder = createKeyFinder(randomSource, generatedKeys, resultKeypairs, keyMatcher);
        for (int threadIndex = 0; threadIndex < 4; threadIndex++) {
            new Thread(keyFinder).start();
        }
        while (true) {
            FreenetURI[] keypair = resultKeypairs.poll(1000, MILLISECONDS);
            if (keypair != null) {
                System.out.println(format("\r%s <- %s", keypair[1], keypair[0]));
                foundKeys++;
                continue;
            }
            long timeSpent = currentTimeMillis() - firstOutput;
            System.err.print(format("\r%d/s, %.3f/s",
                    generatedKeys.get() / MILLISECONDS.toSeconds(timeSpent),
                    (double) foundKeys / MILLISECONDS.toSeconds(timeSpent)));
        }
    }

    private static KeyMatcher createKeyMatcher(final String[] arguments) {
        return new KeyMatcher() {
            @Override
            public boolean matches(String requestUriWithoutKeyType) {
                for (String argument : arguments) {
                    if (requestUriWithoutKeyType.toLowerCase().startsWith(argument.toLowerCase())) {
                        return true;
                    }
                }
                return false;
            }
        };
    }

    private static Runnable createKeyFinder(final RandomSource randomSource, final AtomicLong generatedKeys, final BlockingQueue<FreenetURI[]> resultKeypairs, final KeyMatcher keyMatcher) {
        return new Runnable() {
            @Override
            public void run() {
                try {
                    while (true) {
                        generateKey();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }

            private void generateKey() throws InterruptedException {
                InsertableClientSSK clientSSK = createRandom(randomSource, "");
                generatedKeys.incrementAndGet();
                if (keyMatcher.matches(clientSSK.getURI().toString().substring(4))) {
                    resultKeypairs.put(new FreenetURI[]{clientSSK.getInsertURI(), clientSSK.getURI()});
                }
            }
        };
    }

    private interface KeyMatcher {

        boolean matches(String requestUri);

    }

}