Given the ubiquity of touchscreen smartphones and tablets, researchers from the University of North Carolina conducted an experiment to explore the feasibility of spying on users typing on virtual keyboards. As part of the study titled "iSpy: Automatic Reconstruction of Typed Input from Compromising Reflections," the researchers noted that while users are generally cautious and take steps to prevent shoulder surfing, the same is not true of someone facing them across the aisle on the morning bus ride or seated a few seats away.

Using low cost commodity video cameras, the researchers captured reflections off sunglasses from up to 100 feet away. In their experiments conducted in realistic environments, the researchers successfully compensated for variables such as arbitrary camera and device positioning and motion, and could construct captured data with as much as 80 percent accuracy. This works even with the iPhone's built-in camera, though the range decreases and there is a greater dependence on the bigger letters that pop up as characters are typed.

Thankfully, the researchers noted that the application of an anti-reflective coating (found in modern eyeglasses) and simply reducing the brightness of the screen have a "detrimental effect" on any reconstruction. Another key limitation has to be the lower quality of the commodity video cameras used, which results in low pixel resolution at greater distances. Finally, the technique will also not work on keyboards where there is no visual confirmation, such as on larger tablets and devices that use Swype. The full research paper here (.pdf).

For more on this story:
- check out this article at The Register

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