== libfido2

image:https://github.com/yubico/libfido2/workflows/linux/badge.svg["Linux Build Status (github actions)", link="https://github.com/Yubico/libfido2/actions"]
image:https://github.com/yubico/libfido2/workflows/macos/badge.svg["macOS Build Status (github actions)", link="https://github.com/Yubico/libfido2/actions"]
image:https://github.com/yubico/libfido2/workflows/windows/badge.svg["Windows Build Status (github actions)", link="https://github.com/Yubico/libfido2/actions"]
image:https://github.com/yubico/libfido2/workflows/fuzzer/badge.svg["Fuzz Status (github actions)", link="https://github.com/Yubico/libfido2/actions"]
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*libfido2* provides library functionality and command-line tools to
communicate with a FIDO device over USB or NFC, and to verify attestation and
assertion signatures.

*libfido2* supports the FIDO U2F (CTAP 1) and FIDO2 (CTAP 2) protocols.

For usage, see the `examples/` directory.

=== License

*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, OpenBSD, and FreeBSD.

=== Documentation

Documentation is available in troff and HTML formats. An
https://developers.yubico.com/libfido2/Manuals/[online mirror of *libfido2*'s documentation]
is also available.

=== Bindings

* .NET: https://github.com/borrrden/Fido2Net[Fido2Net]
* Go: https://github.com/keys-pub/go-libfido2[go-libfido2]
* Perl: https://github.com/jacquesg/p5-FIDO-Raw[p5-FIDO-Raw]
* Rust: https://github.com/PvdBerg1998/libfido2[libfido2]

=== Releases

The current release of *libfido2* is 1.16.0. Signed release tarballs are
available at Yubico's
https://developers.yubico.com/libfido2/Releases[release page].

=== Dependencies

*libfido2* depends on https://github.com/pjk/libcbor[libcbor],
https://www.openssl.org[OpenSSL] 1.1 or newer, and https://zlib.net[zlib].
On Linux, libudev
(part of https://www.freedesktop.org/wiki/Software/systemd[systemd]) is also
required.

=== Installation

==== Fedora 34 and later

  $ sudo dnf install libfido2 libfido2-devel fido2-tools

==== Ubuntu 20.04 (Focal) and later

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

Alternatively, newer versions of *libfido2* are available in Yubico's PPA.
Follow the instructions for Ubuntu 18.04 (Bionic) below.

==== Ubuntu 18.04 (Bionic)

  $ sudo apt install software-properties-common
  $ sudo apt-add-repository ppa:yubico/stable
  $ sudo apt update
  $ sudo apt install libfido2-1 libfido2-dev libfido2-doc fido2-tools

On Linux, you may need to add a udev rule to be able to access the FIDO
device. 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"
----

==== macOS

  $ brew install libfido2

==== Windows

Please consult Yubico's
https://developers.yubico.com/libfido2/Releases[release page] for ARM, ARM64,
Win32, and Win64 artefacts.

=== Building from source

On UNIX-like systems:

  $ cmake -B build
  $ make -C build
  $ sudo make -C build install

Depending on the platform,
https://www.freedesktop.org/wiki/Software/pkg-config/[pkg-config] may need to
be installed, or the PKG_CONFIG_PATH environment variable set. For complete,
OS-specific build instructions, please refer to the `.actions/`
(Linux, macOS, BSD) and `windows/` directories.

=== Build-time Customisation

*libfido2* supports a number of CMake options. Some of the options require
additional dependencies. Options that are disabled by default are not
officially supported.

[%autowidth.stretch]
|===
|*Option*           |*Description*                            |*Default*
| BUILD_EXAMPLES    | Build example programs                  | ON
| BUILD_MANPAGES    | Build man pages                         | ON
| BUILD_SHARED_LIBS | Build a shared library                  | ON
| BUILD_STATIC_LIBS | Build a static library                  | ON
| BUILD_TOOLS       | Build auxiliary tools                   | ON
| FUZZ              | Enable fuzzing instrumentation          | OFF
| NFC_LINUX         | Enable netlink NFC support on Linux     | ON
| USE_HIDAPI        | Use hidapi as the HID backend           | OFF
| USE_PCSC          | Enable experimental PCSC support        | OFF
| USE_WINHELLO      | Abstract Windows Hello as a FIDO device | ON
|===

The USE_HIDAPI option requires https://github.com/libusb/hidapi[hidapi]. The
USE_PCSC option requires https://github.com/LudovicRousseau/PCSC[pcsc-lite] on
Linux.

=== Development

Please use https://github.com/Yubico/libfido2/discussions[GitHub Discussions]
to ask questions and suggest features, and
https://github.com/Yubico/libfido2/pulls[GitHub pull-requests] for code
contributions.

=== Reporting bugs

Please use https://github.com/Yubico/libfido2/issues[GitHub Issues] to report
bugs. To report security issues, please contact security@yubico.com. A PGP
public key can be found at
https://www.yubico.com/support/security-advisories/issue-rating-system/.
