Looking for another application/technology:

A number of years ago, I read about a novel way to authenticate and log on to a laptop. The user simply had to hold the laptop in the air and execute a simple series of tilts and flips to the laptop. By logging accelerometer data, this creates a unique signature for the user. Even if an attacker watched and repeated the exact same motions, the attacker could not replicate the user's movements closely enough.

I am looking for information about this technology again, but I can't find anything. It may have been an actual feature on a laptop, or it may have just been a research project. I think I read about it in a magazine like Wired.

Does anyone have more information about authentication via unique accelerometer signatures?

Here are the closest articles I have been able to find:

• Knock-based commands for your Linux laptop
• Shake Well Before Use: Authentication Based on Accelerometer Data[PDF]
• Inferring Identity using Accelerometers in Television Remote Controls
• User Evaluation of Lightweight User Authentication with a Single Tri-Axis Accelerometer
• Identifying Users of Portable Devices from Gait Pattern with Accelerometers[PDF]
• 3D Signature Biometrics Using Curvature Moments[PDF]
• MoViSign: A novel authentication mechanism using mobile virtual signatures