I can setup SSH keypair without Fido U2F as described SSH-agent working over many servers without retyping? Some flag? in the thread. Two step verification would be very good: password for the private key and Fido U2F verification too. I am not sure if we need here Fido/YubiKey server too, as instructed in the thread Yubico Linux Login.My motivation is that I forget so often my passwords which are very long if used in 1-step verifications. 1-step verification is also weak itself although how long and difficult the password is. Therefore, I would like to have 2-step verification in my Debian with keys, because I think keys can improve much security. Ticket sent to YubiKey team 22nd Feb 2017Dear Sir/Madam, We are thinking how to get 2-step verification with your key and keys in the following thread. Improvements are needed in FIDO U2F and OpenSSH parts. I am thinking how we can push the thing forward with You. Please, say what we can do because the feature request is rather blocked at the moment. Ticket in OpenSSH part: https://bugzilla.mindrot.org/show_bug.cgi?id=2319Thread about the feature request: http://unix.stackexchange.com/q/346771/16920Best regards, LeoOS: Debian 8.7Hardware: Asus Zenbook UX303UBTickets: #2319 (Jakuje)Fido U2F key: YubiKey 4    
How to use YubiKeys with SSH keys in 2-step verification?
ssh;security;yubikey;fido u2f;2 factor authentication