Pretty cool paper: they train LDA model to predict password from sound of taps with 61% accuracy! This required background app running on device with access to microphone. The obvious extension is to predict password from video clip of someone entering it!
Honestly, I'd really prefer that to all the times when I have slightly damp fingers an my fingerprint sensor is not registering, or it is causing issues with swiping.
So does using an alphanumeric passcode instead. Especially if you include capital letters and punctuation that you can access with a swipe starting at the shift or number key (so you never actually tap the key that produces the input).
Yet another reason why the mobile OS should (freeze / swap out / disable) an app upon entering the background ... at a minimum the user needs to have more control over degree to which above happens ... of course powers to be love a smartphones current total lack of such privacy
> In controlled settings, our prediction model can on average classify the PIN entered 43% of the time and pattern 73% of the time within 5 attempts when selecting from a test set of 50 PINs and 50 patterns. In uncontrolled settings, while users are walking, our model can still classify 20% of the PINs and 40% of the patterns within 5 attempts.
