openssh-sk-winhello VS libfido2

For Windows, it seems it's possible[0, see footnote], however there are problems like general incompatibilities [1], and official support status is " We have this in our backlog. At this point it's not prioritized.".

0: https://github.com/tavrez/openssh-sk-winhello

0.footnote: "Windows Hello also supports other types of authenticators like internal TPM device(if they support generating ECDSA or Ed25519 keys, they can be used instead of FIDO/U2F security keys)."

1: https://github.com/tavrez/openssh-sk-winhello/issues

2: https://github.com/PowerShell/Win32-OpenSSH/issues/1804#issu...

Awesome article! Also found this tool (tavrez/OpenSsh-sk-winhello) for windows that lets you do this without admin access

Which is also how they are generated when retrieving them on a new computer via ssh-keygen -K since I used the application=ssh:yubikey_5 flag when first generating them. So something like ssh-keygen -t ed25519-sk -O resident -O application=ssh:yubikey_5c, but because I am on Windows I also had the -w winhello.dll flag (In case anyone stumbles on this question)

This is what i used but YMMV https://github.com/tavrez/openssh-sk-winhello/releases/tag/v2.0.0

> Because AFAIK, (Fido) yubikey support is still missing.

Correct, hopefully Microsoft will provide an updated SSH client soon. It only requires recompiling OpenSSH with the correct flags.

Alternatively, use these build instruction for openssh with FIDO for windows:

https://gist.github.com/martelletto/6a7cf806c6433ac9ce71d66a...

> Using either the PKCS#11 support or the gpg applet requires some extra piece of software

For those wanting to do that, here are some ways:

Using a premade dll:

https://github-wiki-see.page/m/mooltipass/minible/wiki/Setti...

Or with a middleware:

https://github.com/mgbowen/windows-fido-bridge

Using the Hello API:

https://github.com/tavrez/openssh-sk-winhello

Given how many people came with their own ways, I believe there's enough demand for Microsoft to fix that.

My knowledge of WebAuthn is limited but their invocation of the relevant API seems like it should work for fingerprints also.

[1] https://github.com/tavrez/openssh-sk-winhello

udev? yeah you should check that. https://github.com/Yubico/libfido2/blob/main/udev/70-u2f.rules Reload the udev rules after you change them if you do change them, and unplug the device, wait 15 seconds, plug it in again.

It's not extremely difficult at all to implement these! Heck, even at Google we use LibFido2 which is a free-to-use library (you can find it here if you want: https://github.com/Yubico/libfido2). Of course Google's version is a bit different and the creator of LibFido2 now works here, but all of these 2FA methods aren't particularly difficult to implement in the sense that most of the work (libraries, standards, exact specifications) is already done.

It could be possible yes. Libraries like https://github.com/Yubico/libfido2 already abstract away external keys (via CTAP) and the Windows WebAuthn API, which allows you to use Windows Hello for signing in using eg a Logitech Brio webcam.

https://fidoalliance.org https://loginwithfido.com https://w3.org/TR/webauthn-2/ https://fidoalliance.org/specs/fido-v2.1-ps-20210615/fido-client-to-authenticator-protocol-v2.1-ps-20210615.html https://github.com/yubico/Python-Fido2 https://github.com/yubico/libfido2

They suggest using this libfido2 library to connect with the hardware devices. I don't really know much about OSS licenses and which are the most "free" so you'll have to decide that for yourself.