Crypt:...Server(3pm)

💖 Crypt::U2F::Server 💖

okay bestie, so this is a page from the User Contributed Perl Documentation section of the manual, and it's about Crypt::U2F::Server — the low-level wrapper around the U2F two-factor authentication C library, server side. sit down, hydrate, let's get into it 🫶

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✨ NAME ✨

Crypt::U2F::Server — it's a low level wrapper around the U2F two factor authentication C library (and it lives on the server side, before you ask) 💅

✨ SYNOPSIS ✨

use Crypt::U2F::Server;

that's it. that's the whole vibe. literally one line 🎀

✨ DESCRIPTION ✨

so bestie. this is a very low level wrapper around the original C library. and, like, no cap — you probably shouldn't use it?? use Crypt::U2F::Server::Simple instead. i'm being so serious. 🙈

this API is subject to change, and it changes depending on the underlying library, the weather, and the whims of the developer. the weather. bestie. 🌦️

if you decide to use it anyway (main character energy, i respect it), it would probably be a good idea to specify the exact version number of Crypt::U2F::Server to use.

✨ INSTALLATION ✨

this module requires the Yubico u2f-server shared library installed. please see the official project page at <https://developers.yubico.com/libu2f-server/> for how to do that. it is what it is 🐚

✨ NO MULTITHREADING / MULTI INSTANCES ✨

the way this is currently implemented, i doubt very much that multithreading — or even use in more than one instance in your program — will work. Multi-Forking should be OK, though, if you only call u2fclib_init() after forking, but this isn't tested as of yet. so, like, fingers crossed 🤞

the problem is how u2fclib_init() and u2fclib_deInit() are implemented. while the underlying library has a context-handle (not used here), u2fclib_deInit() will tear down everything as far as i can tell. everything. gone. 💀

Crypt::U2F::Server::Simple works around this problem by reference counting and always requiring all values to call the relevant u2fclib_set* functions. slay ✨

🎀 EXPORT 🎀

None by default. (yes, really. nothing. empty. the void. 🕳️)

🌸 Exportable functions 🌸

here's the whole lineup, characters exactly as they should be, don't touch them:

char* u2fclib_calcRegistrationChallenge(void* ctx)
int u2fclib_deInit(void)
int u2fclib_free_context(void* ctx)
char* u2fclib_getError(void)
void* u2fclib_get_context(void)
int u2fclib_init(bool debug)
int u2fclib_setAppID(void* ctx, char* appid)
int u2fclib_setChallenge(void* ctx, char* challenge)
int u2fclib_setKeyHandle(void* ctx, char* buf)
int u2fclib_setOrigin(void* ctx, char* origin)
int u2fclib_setPublicKey(void* ctx, char* buf)
int u2fclib_verifyAuthentication(void* ctx, char* buf)
registrationData_t* u2fclib_verifyRegistration(void* ctx, char* buf)

✨ SEE ALSO ✨

see Crypt::U2F::Server::Simple for the module you should actually be using. i said what i said 👑

✨ BUGS ✨

yes, there should be some in there. 😭 first of all, this is crypto stuff, so it's broken by default (it only depends on the time it takes to happen). yes that's a real sentence and yes i'm quoting it verbatim, do with that what you will.

also, at the moment, this module has seen only very limited testing. 🙈

✨ AUTHOR ✨

• Rene Schickbauer, <rene.schickbauer@magnapowertrain.com>
• Xavier Guimard, <x.guimard@free.fr>

✨ COPYRIGHT AND LICENSE ✨

Adapted as a Perl library by Rene 'cavac' Schickbauer.

this is roughly based on u2f-server.c from Yubico's C library, see <https://developers.yubico.com/libu2f-server/>.

in order for this to work, you need to install that library.

this adaption is (C) 2014-2018 Rene 'cavac' Schickbauer and 2018 Xavier Guimard, but as it is based on Yubico's code, the licence below applies! the licence is not optional bestie, it comes along for the ride 🫶

we, the community, would hereby thank Yubico for open sourcing their code! 💖

/*
* Copyright (c) 2014 Yubico AB
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

and that's the whole page!! you read all of it, i'm so proud 🥹 this was rendered out of perl v5.42.3, dated 2026-08-21, and it's the Crypt::...Server(3pm) page. go drink some water, you've earned it 💅✨