Recognizing Speech from Smartphone Gyroscopes (2014)
crypto.stanford.edu
crypto.stanford.edu
On Android (like, 4.2 or something) with Firefox, the page and the CSV just displays `null` for alpha, beta and gamma. And the calculated rate is 9.1 samples per second, which seems way too low to extract any speech details even if the data were valid.
This is distinct from the "No device motion data" message presented on my desktop though. So it seems to me that the page sees that a gyroscope is present, and requests data from it, but Firefox is just feeding it null values?
I haven't tried the apk yet.
If one applies a 100 Hz filter to some samples of human speech (even low-pitched male voices, as the authors of the paper suggest), the result is (unsurprisingly) the sort of "womp womp" that one might expect to hear from a car with giant subwoofers, not anything containing recognizable words.
The authors of the paper admit that they were unable to recover the content of speech, but focused on identifying the speaker. That's a long way from capturing credit card numbers (which is what their promo video implies).
Basically, I'll believe it when I see it. The approach is really interesting, though, and I think could be useful for other things.
But it's impossible to filter a signal in the time domain without introducing a phase shift (i.e. a delay). As a result, you cannot remove that extra frequency information before sending the data to an application without making sacrifices on latency.