u2f(4)

u2f4

Fido/u2f usb security keys

Usage

device u2f

In loader.conf(5): u2f_load="YES"

In sysctl.conf(5): hw.hid.u2f.debug

Overview

The u2f driver provides support for FIDO/U2F-compatible USB security keys. They are Human Interface Devices (HID) which can be accessed via the /dev/u2f/N interface.

The driver is compatible with the read(2), write(2), and ioctl(2) operations of the generic uhid(4) device but only accepts the optional HID ioctl(2) calls from u2f group users.

Hardware

The u2f driver supports FIDO/U2F-compatible USB security keys.

Sysctl variables

The following variables are available as both sysctl(8) variables and loader(8) tunables:

hw.hid.u2f.debug

Debug output level, where 0 is debugging disabled and larger values increase debug message verbosity. Default is 0.

Files

/dev/u2f/*

Releases

3 releases since FreeBSD 15.0-RELEASE; the text changed 1 time.

  1. 15.0–15.1
  2. 16.0

History

The u2f driver first appeared in FreeBSD 15.0.

Authors

The u2f driver was written by Vladimir Kondratyev ⟨[email protected]⟩.

This manual page was written by Vladimir Kondratyev ⟨[email protected]⟩ based on the OpenBSD fido(4) manual page.

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.