Essentially, Google’s Authenticator is a program that generates one time passwords (OTPs) for users, which are then employed as a second factor of authentication in conjunction with a “normal” password.

“OTPs work by having a shared secret and a synchronized clock on two devices,” HackADay’s Eric Evenchick explained. “When you generate the password, a hash based on the secret and timestamp is created. This proves that you have access to the secret, and can only be used once.”

As you can see in the video above (Note: hit the CC button for English captions), a Maker by the name of Luca Dentella designed a functioning authentication system using Google Authenticator and his Atmel-powered Arduino. The platform is showcased using a cute mini LEGO of a model house, complete with a door that swings open when the correct code sequence is entered.

“A web app is used to generate a secret that can be configured into the Arduino using an array, and into Google Authenticator using a QR code,” Evenchick added. “The Arduino is using a library that implements Time-based One Time Password authentication (TOTP).”

Interested in learning more about Luca Dentella’s Google Authenticator-Arduino-LEGO mashup? Be sure to check out his official project page here.