[CentOS] ultrasecure sshd server

> How to configure sshd to required both ssh public key and user
> password also? yes, stupid, but required on my setup..

If you want 2 factor authentication, you can add yubikeys. They are little 
usb dongle that provides one-time-password. And the server-side for those is 
open-source if you don't want to use their authentication servers. And they 
are relatively cheap.

We use these here on our border servers to increase security.

Regards,