src/libsystemd/sd-journal/fsprg.h

   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
  10 #include "forward.h"
  11
  12 #ifdef __cplusplus
  13 extern "C" {
  14 #endif
  15
  16 #define FSPRG_RECOMMENDED_SECPAR 1536
  17 #define FSPRG_RECOMMENDED_SEEDLEN (96/8)
  18
  19 size_t FSPRG_mskinbytes(unsigned secpar) _const_;
  20 size_t FSPRG_mpkinbytes(unsigned secpar) _const_;
  21 size_t FSPRG_stateinbytes(unsigned secpar) _const_;
  22
  23 /* Setup msk and mpk. Providing seed != NULL makes this algorithm deterministic. */
  24 int FSPRG_GenMK(void *msk, void *mpk, const void *seed, size_t seedlen, unsigned secpar);
  25
  26 /* Initialize state deterministically in dependence on seed. */
  27 /* Note: in case one wants to run only one GenState0 per GenMK it is safe to use
  28    the same seed for both GenMK and GenState0.
  29 */
  30 int FSPRG_GenState0(void *state, const void *mpk, const void *seed, size_t seedlen);
  31
  32 int FSPRG_Evolve(void *state);
  33
  34 uint64_t FSPRG_GetEpoch(const void *state) _pure_;
  35
  36 /* Seek to any arbitrary state (by providing msk together with seed from GenState0). */
  37 int FSPRG_Seek(void *state, uint64_t epoch, const void *msk, const void *seed, size_t seedlen);
  38
  39 int FSPRG_GetKey(const void *state, void *key, size_t keylen, uint32_t idx);
  40
  41 #ifdef __cplusplus
  42 }
  43 #endif