/*
 *
 * Copyright (c) 2013 - 2017 Lijun Liao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 *
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * THE AUTHOR LIJUN LIAO. LIJUN LIAO DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the XiPKI software without
 * disclosing the source code of your own applications.
 *
 * For more information, please contact Lijun Liao at this
 * address: lijun.liao@gmail.com
 */

package org.xipki.pki.scep.transaction;

import java.security.SecureRandom;
import java.util.Arrays;

import org.xipki.commons.common.util.ParamUtil;

/**
 * @author Lijun Liao
 * @since 2.0.0
 */

public class Nonce {

    private static final SecureRandom RANDOM = new SecureRandom();

    private static final int NONCE_LEN = 16;

    private final byte[] bytes;

    private Nonce(final byte[] bytes, final boolean cloneBytes) {
        ParamUtil.requireNonNull("bytes", bytes);
        ParamUtil.requireRange("bytes.length", bytes.length, 16, 16);
        this.bytes = cloneBytes ? Arrays.copyOf(bytes, bytes.length) : bytes;
    }

    public Nonce(final byte[] bytes) {
        this(bytes, true);
    }

    public byte[] getBytes() {
        return Arrays.copyOf(bytes, bytes.length);
    }

    public static Nonce randomNonce() {
        byte[] bytes = new byte[NONCE_LEN];
        RANDOM.nextBytes(bytes);
        return new Nonce(bytes, false);
    }

}