If you’re like me, you’ve wondered how sites like Facebook, Reddit, and Instagram are able to tell you whether a username has been taken so quickly. It seemed like these services were able to search through hundreds of millions of user records to verify the uniqueness of a

Cybersecurity has always been a weak point for me and after setting up Authy for the n-th time, it seemed as good a time as any to take a deep dive and figure out exactly how these time-based one-time password algorithms worked. Basic Overview At the highest level, the passcodes