Files
c-toxcore/toxcore/shared_key_cache.h
2026-01-27 22:35:47 +00:00

58 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2022-2026 The TokTok team.
*/
#ifndef C_TOXCORE_TOXCORE_SHARED_KEY_CACHE_H
#define C_TOXCORE_TOXCORE_SHARED_KEY_CACHE_H
#include <stdint.h> // uint*_t
#include "attributes.h"
#include "crypto_core.h"
#include "logger.h"
#include "mem.h"
#include "mono_time.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* This implements a cache for shared keys, since key generation is expensive.
*/
typedef struct Shared_Key_Cache Shared_Key_Cache;
/**
* @brief Initializes a new shared key cache.
* @param mono_time Time object for retrieving current time.
* @param self_secret_key Our own secret key of length CRYPTO_SECRET_KEY_SIZE,
* it must not change during the lifetime of the cache.
* @param timeout Number of milliseconds, after which a key should be evicted.
* @param keys_per_slot There are 256 slots, this controls how many keys are stored per slot and the size of the cache.
* @return nullptr on error.
*/
Shared_Key_Cache *_Nullable shared_key_cache_new(const Logger *_Nonnull log, const Mono_Time *_Nonnull mono_time, const Memory *_Nonnull mem, const uint8_t *_Nonnull self_secret_key, uint64_t timeout,
uint8_t keys_per_slot);
/**
* @brief Deletes the cache and frees all resources.
* @param cache Cache to delete or nullptr.
*/
void shared_key_cache_free(Shared_Key_Cache *_Nullable cache);
/**
* @brief Looks up a key from the cache or computes it if it didn't exist yet.
* @param cache Cache to perform the lookup on.
* @param public_key Public key, used for the lookup and computation.
*
* @return The shared key of length CRYPTO_SHARED_KEY_SIZE, matching the public key and our secret key.
* @return nullptr on error.
*/
const uint8_t *_Nullable shared_key_cache_lookup(Shared_Key_Cache *_Nonnull cache, const uint8_t public_key[_Nonnull CRYPTO_PUBLIC_KEY_SIZE]);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* C_TOXCORE_TOXCORE_SHARED_KEY_CACHE_H */