Two-Factor Authentication With Google Authenticator And LDAP
Introduction
Earlier this year Google released their time-based one-time password (TOTP) solution named Google Authenticator. A TOTP is a single-use code with a finite lifetime that can be...
Published Dec 20, 2011
Version 1.0
Great example!
 
 
A related home-grown one-time token/password example. 
 
One Time Passwords via an SMS Gateway with BIG-IP Access Policy Manager
 
https://devcentral.f5.com/s/articles/one-time-passwords-via-an-sms-gateway-with-big-ip-access-policy-manager