edhoc-rs

A microcontroller-optimized implementation of EDHOC in Rust (no_std).

Supports:

• Roles: Initiator, Responder (hacspec only)
• Authentication mode: STAT-STAT
• Cipher suite: 2 (AES-CCM-16-64-128, SHA-256, 8, P-256, ES256, AES-CCM-16-64-128, SHA-256)

Installation

1. Make sure you have Rust installed (see instructions in the website).

2. Download, compile, and run the tests:

git clone git@github.com:openwsn-berkeley/edhoc-rs.git && cd edhoc-rs
cargo build
cargo test

Example

In one terminal, run an example CoAP server:

cargo run --bin coapserver

In another one, run the client:

cargo run --bin coapclient

In the output you should find the EDHOC handshake messages and the derived OSCORE secret/salt.

The source code for these examples is at examples/coap/src/bin.

Example: flashing a device and selecting lib version / crypto backend

To build an example application that works on the nrf52840dk, do as follows:

# head to the example `no_std` example
cd ./examples/edhoc-rs-no_std

# build using the hacspec version of the lib, and software-based crypto
cargo build --target="thumbv7em-none-eabihf" --no-default-features --features="hacspec-psa, rtt" --release

# build using the rust version of the lib, and hardware-accelerated crypto
cargo build --target="thumbv7em-none-eabihf" --no-default-features --features="rust-cryptocell310, rtt"

To build and flash to the board, replace the word build with embed in the commands above (you may need to cargo install cargo-embed).

For example: cargo embed --target="thumbv7em-none-eabihf" --no-default-features --features="cryptocell310, rtt"

To see more examples on how to build it using different crypto backends and workspace features, check the Github Actions file.

Directory structure

This library is structured as a Workspace, a feature from Cargo which makes it easy to manage more than one package / application in the same repository. Here are its the main folders:

• lib: The main library for the EDHOC implementation.
• examples: Example applications that demonstrate how to use the EDHOC library. There are several subdirectories, each containing a different example application (e.g., coap, edhoc-rs-cc2538, edhoc-rs-no_std).
• consts: Defines constants used throughout the project.
• crypto: Implement wrappers from cryptographic operations that work in different targets (native, nrf52840 with and without hardware-accelerated crypto, etc.).
• hacspec: Leverages the Hacspec cryptographic specification language to implement the EDHOC protocol (the RFC stuff).

To see how to select different features, check the Github Actions file.