mirror of
https://github.com/espressif/esp-idf.git
synced 2024-10-05 20:47:46 -04:00
163 lines
8.8 KiB
ReStructuredText
163 lines
8.8 KiB
ReStructuredText
ESP-TLS
|
|
=======
|
|
|
|
Overview
|
|
--------
|
|
|
|
The ESP-TLS component provides a simplified API interface for accessing the commonly used TLS functionality.
|
|
It supports common scenarios like CA certification validation, SNI, ALPN negotiation, non-blocking connection among others.
|
|
All the configuration can be specified in the ``esp_tls_cfg_t`` data structure. Once done, TLS communication can be conducted using the following APIs:
|
|
|
|
* :cpp:func:`esp_tls_conn_new`: for opening a new TLS connection.
|
|
* :cpp:func:`esp_tls_conn_read`: for reading from the connection.
|
|
* :cpp:func:`esp_tls_conn_write`: for writing into the connection.
|
|
* :cpp:func:`esp_tls_conn_delete`: for freeing up the connection.
|
|
|
|
Any application layer protocol like HTTP1, HTTP2 etc can be executed on top of this layer.
|
|
|
|
Application Example
|
|
-------------------
|
|
|
|
Simple HTTPS example that uses ESP-TLS to establish a secure socket connection: :example:`protocols/https_request`.
|
|
|
|
Tree structure for ESP-TLS component
|
|
-------------------------------------
|
|
.. highlight:: none
|
|
|
|
::
|
|
|
|
├── esp_tls.c
|
|
├── esp_tls.h
|
|
├── esp_tls_mbedtls.c
|
|
├── esp_tls_wolfssl.c
|
|
└── private_include
|
|
├── esp_tls_mbedtls.h
|
|
└── esp_tls_wolfssl.h
|
|
|
|
The ESP-TLS component has a file :component_file:`esp-tls/esp_tls.h` which contain the public API headers for the component. Internally ESP-TLS component uses one
|
|
of the two SSL/TLS Libraries between mbedtls and wolfssl for its operation. API specific to mbedtls are present in :component_file:`esp-tls/private_include/esp_tls_mbedtls.h` and API
|
|
specific to wolfssl are present in :component_file:`esp-tls/private_include/esp_tls_wolfssl.h`.
|
|
|
|
Underlying SSL/TLS Library Options
|
|
----------------------------------
|
|
The ESP-TLS component has an option to use mbedtls or wolfssl as their underlying SSL/TLS library. By default only mbedtls is available and is
|
|
used, wolfssl SSL/TLS library is available publicly at https://github.com/espressif/esp-wolfssl. The repository provides wolfssl component in binary format, it
|
|
also provides few examples which are useful for understanding the API. Please refer the repository README.md for
|
|
information on licensing and other options. Please see below option for using wolfssl in your project.
|
|
|
|
.. note:: `As the library options are internal to ESP-TLS, switching the libries will not change ESP-TLS specific code for a project.`
|
|
|
|
How to use wolfssl with ESP-IDF
|
|
-------------------------------
|
|
There are two ways to use wolfssl in your project
|
|
|
|
1) Directly add wolfssl as a component in your project with following three commands.::
|
|
|
|
(First change directory (cd) to your project directory)
|
|
mkdir components
|
|
cd components
|
|
git clone https://github.com/espressif/esp-wolfssl.git
|
|
|
|
2) Add wolfssl as an extra component in your project.
|
|
|
|
* Download wolfssl with::
|
|
|
|
git clone https://github.com/espressif/esp-wolfssl.git
|
|
|
|
* Include esp-wolfssl in ESP-IDF with setting EXTRA_COMPONENT_DIRS in CMakeLists.txt/Makefile of your project as done in `wolfssl/examples <https://github.com/espressif/esp-wolfssl/tree/master/examples>`_. For reference see Optional Project variables in :doc:`build-system.</api-guides/build-system>`
|
|
|
|
After above steps, you will have option to choose wolfssl as underlying SSL/TLS library in configuration menu of your project as follows::
|
|
|
|
idf.py/make menuconfig -> ESP-TLS -> choose SSL/TLS Library -> mbedtls/wolfssl
|
|
|
|
Comparison between mbedtls and wolfssl
|
|
--------------------------------------
|
|
The following table shows a typical comparison between wolfssl and mbedtls when :example:`protocols/https_request` example `(which has server authentication)` was run with both
|
|
SSL/TLS libraries and with all respective configurations set to default.
|
|
`(mbedtls IN_CONTENT length and OUT_CONTENT length were set to 16384 bytes and 4096 bytes respectively)`
|
|
|
|
+---------------------+------------+-----------+
|
|
| Property | Wolfssl | Mbedtls |
|
|
+=====================+============+===========+
|
|
| Total Heap Consumed | ~19 Kb | ~37 Kb |
|
|
+---------------------+------------+-----------+
|
|
| Task Stack Used | ~2.2 Kb | ~3.6 Kb |
|
|
+---------------------+------------+-----------+
|
|
| Bin size | ~858 Kb | ~736 Kb |
|
|
+---------------------+------------+-----------+
|
|
|
|
.. note:: `These values are subject to change with change in configuration options and version of respective libraries`.
|
|
|
|
.. only:: esp32
|
|
|
|
ATECC608A (Secure Element) with ESP-TLS
|
|
--------------------------------------------------
|
|
|
|
ESP-TLS provides support for using ATECC608A cryptoauth chip with ESP32-WROOM-32SE.
|
|
Use of ATECC608A is supported only when ESP-TLS is used with mbedTLS as its underlying SSL/TLS stack.
|
|
ESP-TLS uses mbedtls as its underlying TLS/SSL stack by default unless changed manually.
|
|
|
|
.. note:: ATECC608A chip on ESP32-WROOM-32SE must be already configured and provisioned, for details refer `esp_cryptoauth_utility <https://github.com/espressif/esp-cryptoauthlib/blob/master/esp_cryptoauth_utility/README.md#esp_cryptoauth_utility>`_
|
|
|
|
To enable the secure element support, and use it in you project for TLS connection, you will have to follow below steps
|
|
|
|
1) Add `esp-cryptoauthlib <https://github.com/espressif/esp-cryptoauthlib>`_ in your project, for details please refer `esp-cryptoauthlib with ESP_IDF <https://github.com/espressif/esp-cryptoauthlib#how-to-use-esp-cryptoauthlib-with-esp-idf>`_
|
|
|
|
2) Enable following menuconfig option::
|
|
|
|
menuconfig->Component config->ESP-TLS->Use Secure Element (ATECC608A) with ESP-TLS
|
|
|
|
3) Select type of ATECC608A chip with following option::
|
|
|
|
menuconfig->Component config->esp-cryptoauthlib->Choose Type of ATECC608A chip
|
|
|
|
to know more about different types of ATECC608A chips and how to obtain type of ATECC608A connected to your ESP module please visit `ATECC608A chip type <https://github.com/espressif/esp-cryptoauthlib/blob/master/esp_cryptoauth_utility/README.md#find-type-of-atecc608a-chip-connected-to-esp32-wroom32-se>`_
|
|
|
|
4) Enable use of ATECC608A in ESP-TLS by providing following config option in `esp_tls_cfg_t`
|
|
|
|
.. code-block:: c
|
|
|
|
esp_tls_cfg_t cfg = {
|
|
/* other configurations options */
|
|
.use_secure_element = true,
|
|
};
|
|
|
|
.. only:: esp32s2
|
|
|
|
.. _digital-signature-with-esp-tls:
|
|
|
|
Digital Signature with ESP-TLS
|
|
------------------------------
|
|
ESP-TLS provides support for using the Digital Signature (DS) with ESP32-S2.
|
|
Use of the DS for TLS is supported only when ESP-TLS is used with mbedTLS (default stack) as its underlying SSL/TLS stack.
|
|
For more details on Digital Signature, please refer to the :doc:`Digital Signature Documentation </api-reference/peripherals/ds>`. The technical details of Digital Signature such as
|
|
how to calculate private key parameters can be found at `{IDF_TARGET_NAME} Technical Reference Manual <{IDF_TARGET_TRM_EN_URL}>`_.
|
|
The DS peripheral must be configured before it can be used to perform Digital Signature, see `Configure the DS Peripheral` in :doc:`Digital Signature </api-reference/peripherals/ds>`.
|
|
|
|
.. note:: As the DS peripheral support is only available for ESP32-S2, the idf-target should be set to ESP32-S2. See `Selecting the Target` in :doc:`build-system.</api-guides/build-system>`.
|
|
|
|
The DS peripheral must be initlized with the required encrypted private key parameters (obtained when the DS peripheral is configured). ESP-TLS internally initializes the DS peripheral when
|
|
provided with the required DS context (DS parameters). Please see the below code snippet for passing the DS context to esp-tls context. The DS context passed to the esp-tls context should not be freed till the TLS connection is deleted.
|
|
|
|
.. code-block:: c
|
|
|
|
#include "esp_tls.h"
|
|
esp_ds_data_ctx_t *ds_ctx;
|
|
/* initialize ds_ctx with encrypted private key parameters, which can be read from the nvs or
|
|
provided through the application code */
|
|
esp_tls_cfg_t cfg = {
|
|
.clientcert_buf = /* the client cert */,
|
|
.clientcert_bytes = /* length of the client cert */,
|
|
/* other configurations options */
|
|
.ds_data = (void *)ds_ctx,
|
|
};
|
|
|
|
.. note:: When using Digital Signature for the TLS connection, along with the other required params, only the client cert (`clientcert_buf`) and the DS params (`ds_data`) are required and the client key (`clientkey_buf`) can be set to NULL.
|
|
|
|
* An example of mutual authentication with the DS peripheral can be found at :example:`ssl mutual auth<protocols/mqtt/ssl_mutual_auth>` which internally uses (ESP-TLS) for the TLS connection.
|
|
|
|
API Reference
|
|
-------------
|
|
|
|
.. include-build-file:: inc/esp_tls.inc
|