Candy Stick

There have been some API changes to the fido2 library, i.e., this project will currently not compile. Please see candy-stick-nrf for a working example.

CTAP2 firmware

src/
  |-ctaphid/
  | |-response.zig  (for generating CTAPHID response packets)
  | |-misc.zig      (helper functions and constants)
  | |-commands.zig  (CTAPHID commands)
  |-zigusb.zig      (entry point and USB callbacks)

Build

To build the project you must have installed the Zig compiler on your system.

You also need the arm-none-eabi build tools.

Arch

sudo pacman -S arm-none-eabi-gcc arm-none-eabi-newlib

Ubuntu

sudo apt install gcc-arm-none-eabi

NOTE: Without *-newlib (Arch) you'll get the `fatal error: stdint.h: No such file or directory

include_next <stdint.h>` error.

Also make sure that you've git installed. Then just run ./build from the root directory.

Flash

To flash the firmware install edbg and then just run ./flash from the root directory.

Note: This project targets the SAM E51 Curiosity Nano, i.e. the ATSAME51J20A (ARM Cortex-M4F) chip.

Tools

To use the tools you need to install libfido2.

Arch

sudo pacman -S libfido2

Ubuntu

$ sudo apt install libfido2-1 libfido2-dev libfido2-doc fido2-tools

Build from source

git clone https://github.com/Yubico/libfido2.git
cd libfido2
cmake -B build
make -C build
sudo make -C build install

Important Notes

• The ztap library doesn't sort keys automatically (due to a bug when calling the Zig sort function - program hangs). One must make sure that the returned CBOR is in CTAP canonical CBOR encoding form, e.g. the keys have to be sorted in a specific way. Otherwise libraries like libfido2 will complain.