1 /* SPDX-License-Identifier: LGPL-2.1-or-later */ 2 #pragma once 3 4 /* 5 * fsprg v0.1 - (seekable) forward-secure pseudorandom generator 6 * Copyright © 2012 B. Poettering 7 * Contact: fsprg@point-at-infinity.org 8 * 9 * This library is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU Lesser General Public 11 * License as published by the Free Software Foundation; either 12 * version 2.1 of the License, or (at your option) any later version. 13 * 14 * This library is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with this library; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 22 * 02110-1301 USA 23 */ 24 25 #include <inttypes.h> 26 #include <sys/types.h> 27 28 #include "macro.h" 29 #include "util.h" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 #define FSPRG_RECOMMENDED_SECPAR 1536 36 #define FSPRG_RECOMMENDED_SEEDLEN (96/8) 37 38 size_t FSPRG_mskinbytes(unsigned secpar) _const_; 39 size_t FSPRG_mpkinbytes(unsigned secpar) _const_; 40 size_t FSPRG_stateinbytes(unsigned secpar) _const_; 41 42 /* Setup msk and mpk. Providing seed != NULL makes this algorithm deterministic. */ 43 void FSPRG_GenMK(void *msk, void *mpk, const void *seed, size_t seedlen, unsigned secpar); 44 45 /* Initialize state deterministically in dependence on seed. */ 46 /* Note: in case one wants to run only one GenState0 per GenMK it is safe to use 47 the same seed for both GenMK and GenState0. 48 */ 49 void FSPRG_GenState0(void *state, const void *mpk, const void *seed, size_t seedlen); 50 51 void FSPRG_Evolve(void *state); 52 53 uint64_t FSPRG_GetEpoch(const void *state) _pure_; 54 55 /* Seek to any arbitrary state (by providing msk together with seed from GenState0). */ 56 void FSPRG_Seek(void *state, uint64_t epoch, const void *msk, const void *seed, size_t seedlen); 57 58 void FSPRG_GetKey(const void *state, void *key, size_t keylen, uint32_t idx); 59 60 #ifdef __cplusplus 61 } 62 #endif 63