libfido2 provides library functionality and command-line tools to communicate with a FIDO device over USB, and to verify attestation and assertion signatures.

libfido2 supports the FIDO U2F (CTAP 1) and FIDO 2.0 (CTAP 2) protocols.

For usage, see the examples/ directory.


libfido2 is licensed under the BSD 2-clause license. See the LICENSE file for the full license text.

Supported Platforms

libfido2 is known to work on Linux, MacOS, Windows, and OpenBSD.


Documentation is available in troff and HTML formats. An online mirror of libfido2's documentation is also available.




The current release of libfido2 is 1.5.0. Please consult Yubico’s release page for source and binary releases.

Ubuntu 20.04 (Focal)

sudo apt install libfido2-1
sudo apt install libfido2-dev
sudo apt install libfido2-doc

Alternatively, newer versions of libfido2 are available in Yubico’s PPA. Follow the instructions for Ubuntu 18.04 (Bionic) and 16.04 (Xenial) below.

Ubuntu 18.04 (Bionic) and 16.04 (Xenial)

sudo apt install software-properties-common
sudo apt-add-repository ppa:yubico/stable
sudo apt update
sudo apt install libfido2-dev


brew install libfido2

Or from source, on UNIX-like systems:

(rm -rf build && mkdir build && cd build && cmake ..)
make -C build
sudo make -C build install

Depending on the platform, pkg-config may need to be installed, or the PKG_CONFIG_PATH environment variable set.

libfido2 depends on libcbor and OpenSSL. On Linux, libudev (part of systemd) is also required.

For complete, OS-specific installation instructions, please refer to the .actions/ (Linux, MacOS) and windows/ directories.

On Linux, you will need to add a udev rule to be able to access the FIDO device, or run as root. For example, the udev rule may contain the following:

#udev rule for allowing HID access to Yubico devices for FIDO support.

KERNEL=="hidraw*", SUBSYSTEM=="hidraw", \
  MODE="0664", GROUP="plugdev", ATTRS{idVendor}=="1050"

On Windows 1903 and newer versions, access to FIDO devices has been restricted to applications using the operating system’s native API. Use of libfido2 is still possible in privileged applications.