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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
/*
* fsprg v0.1 - (seekable) forward-secure pseudorandom generator
* Copyright © 2012 B. Poettering
* Contact: fsprg@point-at-infinity.org
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <inttypes.h>
#include <sys/types.h>
#include "macro.h"
#ifdef __cplusplus
extern "C" {
#endif
#define FSPRG_RECOMMENDED_SECPAR 1536
#define FSPRG_RECOMMENDED_SEEDLEN (96/8)
size_t FSPRG_mskinbytes(unsigned secpar) _const_;
size_t FSPRG_mpkinbytes(unsigned secpar) _const_;
size_t FSPRG_stateinbytes(unsigned secpar) _const_;
/* Setup msk and mpk. Providing seed != NULL makes this algorithm deterministic. */
int FSPRG_GenMK(void *msk, void *mpk, const void *seed, size_t seedlen, unsigned secpar);
/* Initialize state deterministically in dependence on seed. */
/* Note: in case one wants to run only one GenState0 per GenMK it is safe to use
the same seed for both GenMK and GenState0.
*/
int FSPRG_GenState0(void *state, const void *mpk, const void *seed, size_t seedlen);
int FSPRG_Evolve(void *state);
uint64_t FSPRG_GetEpoch(const void *state) _pure_;
/* Seek to any arbitrary state (by providing msk together with seed from GenState0). */
int FSPRG_Seek(void *state, uint64_t epoch, const void *msk, const void *seed, size_t seedlen);
int FSPRG_GetKey(const void *state, void *key, size_t keylen, uint32_t idx);
#ifdef __cplusplus
}
#endif
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