Support for ed25519-sk SSH keys

[manveru]

trafficstars

Is your feature request related to a problem? Please describe.

Currently the only key type for ed25519 that's supported for SSH is ssh-ed25519, which makes it impossible to use FIDO2 keys (like a Yubikey) to authenticate with the SSH server module.

Describe the solution you'd like

Please add support for the [email protected] key type.

Describe alternatives you've considered

For now I'll have to request my users to use other key types, but given the rising popularity of hardware keys this is not a very good option.

Additional context

The key type has been implemented in OpenSSH for over 4 years, current implementation is at https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/ssh-ed25519-sk.c?rev=1.15&content-type=text/x-cvsweb-markup&only_with_tag=MAIN