esp-idf/components/esp_hw_support/include/esp_hmac.h

95 lines
3.5 KiB
C

/*
* SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#pragma once
#include <stdbool.h>
#include "esp_err.h"
#include "soc/soc_caps.h"
#if !SOC_HMAC_SUPPORTED && !CI_HEADER_CHECK
#error "HMAC peripheral is not supported for the selected target"
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* The possible efuse keys for the HMAC peripheral
*/
typedef enum {
HMAC_KEY0 = 0,
HMAC_KEY1,
HMAC_KEY2,
HMAC_KEY3,
HMAC_KEY4,
HMAC_KEY5,
HMAC_KEY_MAX
} hmac_key_id_t;
/**
* @brief
* Calculate the HMAC of a given message.
*
* Calculate the HMAC \c hmac of a given message \c message with length \c message_len.
* SHA256 is used for the calculation.
*
* @note Uses the HMAC peripheral in "upstream" mode.
*
* @param key_id Determines which of the 6 key blocks in the efuses should be used for the HMAC calculation.
* The corresponding purpose field of the key block in the efuse must be set to the HMAC upstream purpose value.
* @param message the message for which to calculate the HMAC
* @param message_len message length
* return ESP_ERR_INVALID_STATE if unsuccessful
* @param [out] hmac the hmac result; the buffer behind the provided pointer must be a writeable buffer of 32 bytes
*
* @return
* * ESP_OK, if the calculation was successful,
* * ESP_ERR_INVALID_ARG if message or hmac is a nullptr or if key_id out of range
* * ESP_FAIL, if the hmac calculation failed
*/
esp_err_t esp_hmac_calculate(hmac_key_id_t key_id,
const void *message,
size_t message_len,
uint8_t *hmac);
/**
* @brief Use HMAC peripheral in Downstream mode to re-enable the JTAG, if it is not permanently disabled by HW.
* In downstream mode, HMAC calculations performed by peripheral are used internally and not provided back to user.
*
* @param key_id Determines which of the 6 key blocks in the efuses should be used for the HMAC calculation.
* The corresponding purpose field of the key block in the efuse must be set to HMAC downstream purpose.
*
* @param token Pre calculated HMAC value of the 32-byte 0x00 using SHA-256 and the known private HMAC key. The key is already
* programmed to a eFuse key block. The key block number is provided as the first parameter to this function.
*
* @return
* * ESP_OK, if the key_purpose of the key_id matches to HMAC downstread mode,
* The API returns success even if calculated HMAC does not match with the provided token.
* However, The JTAG will be re-enabled only if the calculated HMAC value matches with provided token,
* otherwise JTAG will remain disabled.
* * ESP_FAIL, if the key_purpose of the key_id is not set to HMAC downstream purpose
* or JTAG is permanently disabled by EFUSE_HARD_DIS_JTAG eFuse parameter.
* * ESP_ERR_INVALID_ARG, invalid input arguments
*
* @note Return value of the API does not indicate the JTAG status.
*/
esp_err_t esp_hmac_jtag_enable(hmac_key_id_t key_id, const uint8_t *token);
/**
* @brief Disable the JTAG which might be enabled using the HMAC downstream mode. This function just clears the result generated
* by calling esp_hmac_jtag_enable() API.
*
* @return
* * ESP_OK return ESP_OK after writing the HMAC_SET_INVALIDATE_JTAG_REG with value 1.
*/
esp_err_t esp_hmac_jtag_disable(void);
#ifdef __cplusplus
}
#endif