esphome/noise-c

Readme

Noise-C Library
===============

**Note**: This is a port of the [noise-c](https://github.com/rweather/noise-c) library to build on microcontroller targets. It ships build support for [PlatformIO](https://platformio.org/), [ESP-IDF](https://github.com/espressif/esp-idf), and plain [CMake](https://cmake.org/), so it can be consumed by any microcontroller (or host) project that builds with CMake, not just ESP8266/ESP32.

Noise-C is a plain C implementation of the
[Noise Protocol](http://noiseprotocol.org), intended as a
reference implementation.  It can also be referred to as "Noisy",
which is what you get when you say "Noise-C" too fast.  The code is
distributed under the terms of the MIT license.

The [documentation](http://rweather.github.io/noise-c/index.html)
contains more information on the library, examples, and how to build it.

Using it in a CMake project
---------------------------

The top-level `CMakeLists.txt` detects which build it is running under:

* Under ESP-IDF (`ESP_PLATFORM` set) it registers itself as an IDF component,
  requiring the `esphome__libsodium` component.
* Anywhere else it defines a static library target `noise_c`, also available as
  `esphome::noise_c`, with `include/` and `src/` on its public include path.

So any CMake-based project - a vendor SDK, a bare-metal cross-compile toolchain,
Zephyr, or a host build for tests - can pull it in with `add_subdirectory()` (or
`FetchContent`) and link the target:

```cmake
add_subdirectory(third_party/noise-c)
target_link_libraries(my_app PRIVATE esphome::noise_c)
```

The crypto backend is a compile-time choice made through the `NOISE_USE_*`
macros in `include/noise/defines.h`. The default backend is libsodium; if your
project already defines a `sodium` target before `add_subdirectory()`, the
generic build links against it automatically. Otherwise select the reference
backend (or provide libsodium yourself) before building.

Minimum CMake version for the generic target is 3.13.

This fork is maintained by the [ESPHome](https://esphome.io) project. To report
bugs, contribute, or suggest improvements to it, please open an issue or pull
request on [esphome-libs/noise-c](https://github.com/esphome-libs/noise-c/issues).

The original library was written by Rhys Weatherley; questions about upstream
Noise-C itself belong on [rweather/noise-c](https://github.com/rweather/noise-c).