Secure Your SSH with Google Authenticator OTP - what you need to know
Video shows how to add second authentication factor to your SSH with Google's Authenticator application.
00:00 Introduction
00:33 OTP (one time passwords)
01:55 Hash function
03:21 HOTP (hashed based one time passwords)
05:14 TOTP (time based one time passwords)
06:46 Google Authenticator PAM library
10:16 Configuring Linux PAM and SSH
13:23 Key based authentication with OTP
16:18 Protect SUDO with OTP