What 2FA methods are available?

Currently, we have limited support for 2FA with SSH.

All login nodes of the NHR cluster (glogin[1-13].hpc.gwdg.de) support ed25519-sk and edcsa-sk keys, which use a compatible FIDO2 (hardware) security key for 2FA (not all FIDO2 security keys support it). In the future, all SCC login nodes will support them. If you want to use them, we strongly recommend the non-resident/non-discoverable variant of ed25519-sk (default for ssh-keygen -t ed25519-sk). Resident/discoverable variants require different care to secure. See the FAQ page on keys for more information.

Additional 2FA methods for SSH authentication may come in the future.