/*
 * Copyright (c) 2017, [Ribose Inc](https://www.ribose.com).
 * All rights reserved.
 *
 * This code is originally derived from software contributed to
 * The NetBSD Foundation by Alistair Crooks (agc@netbsd.org), and
 * carried further by Ribose Inc (https://www.ribose.com).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef RNP_S2K_H_
#define RNP_S2K_H_

#include <cstdint>
#include "repgp/repgp_def.h"

typedef struct pgp_s2k_t pgp_s2k_t;

int pgp_s2k_iterated(pgp_hash_alg_t alg,
                     uint8_t *      out,
                     size_t         output_len,
                     const char *   password,
                     const uint8_t *salt,
                     size_t         iterations);

size_t pgp_s2k_decode_iterations(uint8_t encoded_iter);

uint8_t pgp_s2k_encode_iterations(size_t iterations);

// Round iterations to nearest representable value
size_t pgp_s2k_round_iterations(size_t iterations);

size_t pgp_s2k_compute_iters(pgp_hash_alg_t alg, size_t desired_msec, size_t trial_msec);

/** @brief Derive key from password using the information stored in s2k structure
 *  @param s2k pointer to s2k structure, filled according to RFC 4880.
 *  Iterations field may contain encoded ( < 256) or decoded ( > 256) value.
 *  @param password NULL-terminated password
 *  @param key buffer to store the derived key, must have at least keysize bytes
 *  @param keysize number of bytes in the key.
 *  @return true on success or false otherwise
 */
bool pgp_s2k_derive_key(pgp_s2k_t *s2k, const char *password, uint8_t *key, int keysize);

#endif