Jabit/core/src/main/java/ch/dissem/bitmessage/ports/SimplePOWEngine.java

46 lines
1.5 KiB
Java

/*
* Copyright 2015 Christian Basler
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package ch.dissem.bitmessage.ports;
import ch.dissem.bitmessage.utils.Bytes;
import java.security.MessageDigest;
import static ch.dissem.bitmessage.utils.Bytes.inc;
/**
* You should really use the MultiThreadedPOWEngine, but this one might help you grok the other one.
*/
public class SimplePOWEngine implements ProofOfWorkEngine {
@Override
public void calculateNonce(byte[] initialHash, byte[] target, Callback callback) {
byte[] nonce = new byte[8];
MessageDigest mda;
try {
mda = MessageDigest.getInstance("SHA-512");
} catch (Exception e) {
throw new RuntimeException(e);
}
do {
inc(nonce);
mda.update(nonce);
mda.update(initialHash);
} while (Bytes.lt(target, mda.digest(mda.digest()), 8));
callback.onNonceCalculated(initialHash, nonce);
}
}