---
name: "u2f-server"
section: "1"
platform: "linux"
package: "libu2f-server"
version: "1.1.0-7"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/u2f-server"
---

# u2f-server(1)

Yubico Universal 2nd Factor (U2F) Server Tool

## NAME

libu2f-server - Yubico Universal 2nd Factor (U2F) Server Tool

## SYNOPSIS

**libu2f-server** \[*OPTION*\]...

## DESCRIPTION

Perform U2F server-side operations on the command line. Writes challenge to standard output and read responses from standard input.

- **-h**, **--help**

  Print help and exit

- **-V**, **--version**

  Print version and exit

- **-o**, **--origin**=*STRING*

  Origin URL to use.

- **-i**, **--appid**=*STRING*

  Application ID to use.

- **-c**, **--challenge**=*STRING*

  Challenge (Base64-URL encoded) string to use.

- **-a**, **--action**=*ENUM*

  Action to take.  (possible values="register", "authenticate")

- **-k**, **--key-handle**=*STRING*

  A file containing a key-handle

- **-p**, **--user-key**=*STRING*

  A file containing the public user-key

- **-d**, **--debug**

  Print debug information to standard error (default=off)

- **-x**, **--x509cert**=*STRING*

  A file to write the registration attestation certificate to

## REPORTING BUGS

Report bugs at \<https://github.com/Yubico/libu2f-server\>.