[FreeBSD] disable password authentication

you need below configuration on /etc/ssh/sshd_config

especially, you need comment 'UsePAM no'

@@ -62,8 +62,8 @@
#IgnoreRhosts yes

# Change to yes to enable built-in password authentication.
-#PasswordAuthentication no
-#PermitEmptyPasswords no
+PasswordAuthentication no
+PermitEmptyPasswords no

# Change to no to disable PAM authentication
#ChallengeResponseAuthentication yes
@@ -87,7 +87,7 @@
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
-#UsePAM yes
+UsePAM no

#AllowAgentForwarding yes
#AllowTcpForwarding yes