WHY2/include/crypto.h

/*
This is part of WHY2
Copyright (C) 2022 Václav Šmejkal

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 3 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, see <https://www.gnu.org/licenses/>.
*/

#ifndef WHY2_CRYPTO_H
#define WHY2_CRYPTO_H

#ifdef __cplusplus
extern "C" {
#endif

#include <sys/types.h>

#include <why2/flags.h>

//MACROS
#define WHY2_SUM_SEGMENT_SIZE 32 //SEGMENT SIZE FOR CALCULATING SUM
#define WHY2_SUM_BASE_PRIME 31 //PRIME FOR SUM BASE
#define WHY2_SUM_MOD_PRIME 4294967295UL //PRIME FOR SUM MODULUS; 2^32 - 1

#define WHY2_RECOMMENDED_PADDING_RATE(input_len) ((unsigned long) input_len / 3)
#define WHY2_PADDING_NONZERO_TRIES 1024 //HOW MANY RANDOM NUMBERS TO TRY TO GENERATE WHEN PREVENTING 0s

//FUNCTIONS
unsigned long long why2_sum_segment(char *input); //CALCULATE SUM++ FOR input; USED FOR PADDING SEED
why2_bool why2_random(void *dest, size_t size); //WRITE CRYPTO-SECURE RANDOM NUMBER INTO dest
void why2_seed_random(unsigned int seed); //SEED why2_seeded_random OUTPUT
int why2_seeded_random(); //GENERATE RANDOM NUMBER BASED ON SEED PASSED IN why2_seed_random

#ifdef __cplusplus
}
#endif

#endif