After editing the configuration, restart sshd.
Unfortunately, If you cannot would like to use two-factor Yubikey authentication in combination with SSH public key authentication at the current time; , you must pick oneshould look at [http://undeadly.org/cgi?action=article&sid=20130616112437 this Undeadly article] and the ''AuthenticationMethods'' option for openssh.
== PAM two-factor HMAC-SHA1 authentication ==
