circuit-oram-docker/ObliVMGC/com/oblivm/backend/gc/halfANDs/Garbler.java

package com.oblivm.backend.gc.halfANDs;

import java.nio.ByteBuffer;
import java.security.MessageDigest;

import com.oblivm.backend.gc.GCSignal;

final class Garbler {
	private MessageDigest sha1 = null;

	Garbler() {
		try {
			sha1 = MessageDigest.getInstance("SHA-1");
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	ByteBuffer buffer = ByteBuffer.allocate(GCSignal.len + 9);

	public synchronized GCSignal hash(GCSignal lb, long k, boolean b) {
		buffer.clear();
		sha1.update(buffer.put(lb.bytes).putLong(k).put(b ? (byte) 1 : (byte) 0));
		return GCSignal.newInstance(sha1.digest());
	}
}