Explore the intricacies of two-factor authentication (2FA) in this 31-minute conference talk from Passwordscon 2014. Delve into various 2FA types, including SMS, private keys, and PDP-11 systems. Learn about potential vulnerabilities such as stolen passwords, online guessing, and timing attacks. Examine the concept of Password Hash Equivalent and its implications for offline cracking. Gain insights into advanced security measures and understand how to defend against sophisticated hacking techniques in this informative presentation.