Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/**
 * Copyright (C) 2014-2016 Regents of the University of California.
 * @author: Jeff Thompson <jefft0@remap.ucla.edu>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * A copy of the GNU Lesser General Public License is in the file COPYING.
 */

import java.nio.ByteBuffer;
import java.security.InvalidKeyException;

import java.security.NoSuchAlgorithmException;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

public class Main {
    /**
     * Compute the HMAC with SHA-256 of data, as defined in
     * http://tools.ietf.org/html/rfc2104#section-2 .
     * @param key The key byte array.
     * @param data The input byte buffer. This does not change the position.
     * @return The HMAC result.
     */
    public static byte[] computeHmacWithSha256(byte[] key, ByteBuffer data) {
        final String algorithm = "HmacSHA256";
        Mac mac;
        try {
            mac = Mac.getInstance(algorithm);
        } catch (NoSuchAlgorithmException ex) {
            // Don't expect this to happen.
            throw new Error("computeHmac: " + algorithm + " is not supported: " + ex.getMessage());
        }

        try {
            mac.init(new SecretKeySpec(key, algorithm));
        } catch (InvalidKeyException ex) {
            // Don't expect this to happen.
            throw new Error("computeHmac: Can't init " + algorithm + " with key: " + ex.getMessage());
        }
        int savePosition = data.position();
        mac.update(data);
        data.position(savePosition);
        return mac.doFinal();
    }
}