2 Factor Authentication for Linux
From KlavoWiki
Arch Linux
I'll do up a more detailed document but I followed these instruction
https://wiki.archlinux.org/index.php/Google_Authenticator
Install yaourt if not already installed.
pacman -S yaourt
yaourt -S google-authenticator-libpam-git
Note: You will need to edit the build and change the kernel from x686 and x386 to all
Raspbian
The following enforces 2 factor authentication for SSH log-on's and not for the console.
apt-get install libpam-google-authenticator
sshd_config
vi /etc/ssh/sshd_config
on line 48 change ChallengeResponseAuthentication to yes.
ChallengeResponseAuthentication yes
sshd
vi /etc/pam.d/sshd
add the following line to line number 15
auth required pam_google_authenticator.so
You can add the line to line position number 9 if you prefer the auth code asked before the password.