components/esp_hw_support/include/esp_random.h (ESP-IDF)

/* * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #ifndef __ESP_RANDOM_H__ #define __ESP_RANDOM_H__ #include <stddef.h> #include <stdint.h> #ifdef __cplusplus extern "C" { #endif /** * @brief Get one random 32-bit word from hardware RNG * * If Wi-Fi or Bluetooth are enabled, this function returns true random numbers. In other * situations, if true random numbers are required then consult the ESP-IDF Programming * Guide "Random Number Generation" section for necessary prerequisites. * * This function automatically busy-waits to ensure enough external entropy has been * introduced into the hardware RNG state, before returning a new random number. * This delay makes sure the reading frequency does not exceed 15-75 KHz. The actual * value is dependent on the specific chip. More information on this can be found in * components/esp_hw_support/hw_random.c. * * @return Random value between 0 and UINT32_MAX */ uint32_t esp_random(void); /** * @brief Fill a buffer with random bytes from hardware RNG * * @note This function is implemented via calls to esp_random(), so the same * constraints apply. * * @param buf Pointer to buffer to fill with random numbers. * @param len Length of buffer in bytes */ void esp_fill_random(void *buf, size_t len); #ifdef __cplusplus } #endif #endif /* __ESP_RANDOM_H__ */