YubiKey-Guide VS Win32-OpenSSH

Instead, most people generate keypair(s) on an airgapped machine and write them to two Yubikeys. Or write subkeys to a single Yubikey and keep a backup in encrypted form. See https://github.com/drduh/YubiKey-Guide

I'd recommend using the Yubikey as a GPG smartcard[1]. The private key stays on the Yubikey. I also use it for ssh. But make sure you have a backup key or two, just in case the primary Yubikey gives out. FIDO2 and all other regular Yubikey functionality still works with it.

[1]: https://github.com/drduh/YubiKey-Guide

The excellent guide by drduh should be mentioned here: https://github.com/drduh/YubiKey-Guide — I've been using this approach for years to store my OpenPGP keys on Yubikeys and use them for SSH.

I don't generate my keys on devices. That lets me be flexible and keep backups, as well as use the same keys on multiple physical devices. Using a single yubikey is a bad idea, as you're bound to eventually lose it or break it. Hasn't happened to me yet in 5 years, but I expect it to happen.

I followed this guide to generate a master key and three subkey.

See https://github.com/drduh/YubiKey-Guide . Also google for OpenPGP card specifications, they will answer your question

Regarding GPG/SSH keys, there is a great howto: https://github.com/drduh/YubiKey-Guide

I'd be lying if I said I understood all of that. I'm definitely going to do some research ahaha. Someone else on this post sentence this like which they said was very good guide. https://github.com/drduh/YubiKey-Guide

When storing the key on a Yubikey, however, all you need is just the PIN in order to use the key. It can contain numbers, letters, symbols, etc. and can be quite long, so you can treat it as a passphrase for all intents and purposes. There are actually two PIN codes: one regular one, for a read access, and another administrative one, for write access for when you want to modify the gpg applet settings or the key on the Yubikey. There is also a limit to how many times in a row you can enter pins incorrectly, after which the gpg applet gets locked and the only thing you can do is reset it, erasing the PGP keys. See https://github.com/drduh/YubiKey-Guide for more information.

Try follow this guide from DrDuh https://github.com/drduh/YubiKey-Guide/blob/master/README.md

A request for an official answer on CALs for Microsofts' SSH port is about to turn 6 years old:

https://github.com/PowerShell/Win32-OpenSSH/issues/926

I have automated some things "normally" on Windows successfully after installing OpenSSH-win32; https://github.com/PowerShell/Win32-OpenSSH/releases

Are there any other ssh clients that support FIDO2 on windows besides Win32-OpenSSH?

If you're on windows, you need openssh 8.9 to use fido for ssh. https://github.com/PowerShell/Win32-OpenSSH/releases/tag/v8.9.1.0p1-Beta

Unlike Linux, Windows does not come with any tools for setting up an SFTP server. Even FileZilla Server, one of the most popular programs for setting up a FTP server, doesn't support SFTP out of the box. So, are there any other ways to set up an SFTP on Windows? Yes, of course. OpenSSH is a suite of programs for establishing secure connections to the server. sftp-server is one of the utility programs provided by OpenSSH, so this article will walk you through how to set up an SFTP server on Windows using OpenSSH. Originally, OpenSSH was only available on Linux, but Microsoft has ported it to Windows, so you can now use OpenSSH by downloading the zip file from here.

It is mentioned in Win32-OpenSSH's scope that it does not support "VPN Forwarding". Is it the same thing as local/remote port forwarding (ssh -L, and ssh -R)? Can I forward port to and from Windows with Win32-OpenSSH installed on both client and server?

So, personally, I haven't been able to get FIDO2 keys to work at all on Windows, but I didn't try very hard because I'm set-up just fine with GPG for SSH. Apparently there have been a few bugs reported (ref, and linked issue.