OpenSSH server: how to configure keyboard-interactive authentication
Set
ChallengeResponseAuthentication=yes
in your sshd.conf
You need to configure PAM for use with OPIE or OTPW, depending on your Ubuntu version. Once you have a one-time password system in place and properly configured via the /etc/pam.d/sshd module, then you can setup SSH to make use of it.
# /etc/ssh/sshd_config
PasswordAuthentication no
ChallengeResponseAuthentication yes
Don't forget to reload SSH after making changes to the configuration file; otherwise, your changes will not take effect.