/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * 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 2

 * 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 General Public License for more details.

 * 

 * 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. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/nonce.h#1 $

 */

#ifndef NONCE_H

#define NONCE_H

#include "typeDefs.h"

/**

 * Create unique data for the master nonce, using system-specific

 * methods such as the current time and a random number.

 *

 * @param buffer        A buffer of length specified next.

 * @param length        Length of the buffer.

 *

 * @return the amount of the buffer that has been filled with unique data

 **/

size_t createUniqueNonceData(byte *buffer, size_t length);

/**

 * Generate a master nonce, using the specified data.

 *

 * @param data          Some arbitrary information.

 * @param len           The length of the information.

 *

 * @return a number which will be fairly unique

 **/

uint64_t generateMasterNonce(const void *data, size_t len);

/**

 * Deterministically generate a secondary nonce based on an existing

 * nonce and some arbitrary data. Effectively hashes the nonce and

 * the data to produce a new nonce which is deterministic.

 *

 * @param nonce         An existing nonce which is well known.

 * @param data          Some data related to the creation of this nonce.

 * @param len           The length of the data.

 *

 * @return a number which will be fairly unique and depend solely on

 *      the nonce and the data.

 **/

uint64_t generateSecondaryNonce(uint64_t    nonce,

                                const void *data,

                                size_t      len);

#endif // NONCE_H