On Sun, Jul 03, 2016 at 09:19:43PM -0500, Bruce F Bading wrote: > One, the Google Authenticator (OTP authentication). On its own, this is not 2FA. It's single factor ("something you have"). A combination of Google Authenticator _and_ password is 2FA. This is easy to do with PAM. > Two, Public/Private key authentication (pubkeyauthentication = yes) which > supports pass phrase private key authentication. This is 2FA in that you need the private key and the passphrase for it. Unfortunately this can't be enforced at the server; it's client side. That's because the client could _remove_ the passphrase and reduce it to "something you have". The server can't tell the difference. So, from a controls perspective, you have to assume "single factor". -- rgds Stephen _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev