entropy.h

//
// Created by Евгений Крамсаков on 13.01.2022.
//

#ifndef RINGCT_REWORK_ENTROPY_H
#define RINGCT_REWORK_ENTROPY_H

#include "params.h"
#include <stdbool.h>

#define SHA3_512_DIGEST_LENGTH 64
#define EPOOL_HASH_COUNT 10
#define HASH_LEN_UINT16  (SHA3_512_DIGEST_LENGTH/sizeof(uint16_t))
#define HASH_LEN_UINT64  (SHA3_512_DIGEST_LENGTH/sizeof(uint64_t))

typedef struct entropy_s {
    uint64_t   bit_pool;
    uint8_t    char_pool[SHA3_512_DIGEST_LENGTH * EPOOL_HASH_COUNT];
    uint16_t   int16_pool[HASH_LEN_UINT16 * EPOOL_HASH_COUNT];
    uint64_t   int64_pool[HASH_LEN_UINT64 * EPOOL_HASH_COUNT];
    uint8_t    seed[SHA3_512_DIGEST_LENGTH];
    uint32_t   bit_index;
    uint32_t   char_index;
    uint32_t   int16_index;
    uint32_t   int64_index;
} entropy_t;


/* Initialize using a random seed (64 bytes) */
void entropy_init(entropy_t *entropy, const uint8_t *seed);

/* Get one random bit, unsigned char, or 64-bit unsigned integer */
bool entropy_random_bit(entropy_t *entropy);
uint8_t entropy_random_uint8(entropy_t *entropy);
uint16_t  entropy_random_uint16(entropy_t *entropy);
uint64_t  entropy_random_uint64(entropy_t *entropy);

/* Return n random bits
 * - n must be no more than 32
 * - the n bits are low-order bits of the returned integer. */
uint32_t entropy_random_bits(entropy_t *entropy, uint32_t n);

#endif //RINGCT_REWORK_ENTROPY_H