Noise-C Library

Note: This is a port of the noise-c library to build on microcontroller targets. It ships build support for PlatformIO, ESP-IDF, and plain CMake, 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, 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 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:

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 project. To report bugs, contribute, or suggest improvements to it, please open an issue or pull request on esphome-libs/noise-c.

The original library was written by Rhys Weatherley; questions about upstream Noise-C itself belong on rweather/noise-c.