Behavioural biometrics make it possible to identify an individual’s “unique motion fingerprint”,… With the right software, data from a phone’s sensors can reveal details as personal as which part of someone’s foot strikes the pavement first, and how hard; the length of a walker’s stride; the number of strides per minute; and the swing and spring in the walker’s hips and step. It can also work out whether the phone in question is in a handbag, a pocket or held in a hand.

Using these variables, Unifyid, a private company, sorts gaits into about 50,000 distinct types. When coupled with information about a user’s finger pressure and speed on the touchscreen, as well as a device’s regular places of use—as revealed by its gps unit—that user’s identity can be pretty well determined, ction….Behavioural biometrics can, moreover, go beyond verifying a user’s identity. It can also detect circumstances in which it is likely that a fraud is being committed. On a device with a keyboard, for instance, a warning sign is when the typing takes on a staccato style, with a longer-than-usual finger “flight time” between keystrokes. This, according to Aleksander Kijek, head of product at Nethone, a firm in Warsaw that works out behavioural biometrics for companies that sell things online, is an indication that the device has been hijacked and is under the remote control of a computer program rather than a human typist…

Used wisely, behavioural biometrics could be a boon…Used unwisely, however, the system could become yet another electronic spy on people’s privacy, permitting complete strangers to monitor your every action, from the moment you reach for your phone in the morning, to when you fling it on the floor at night.

Excerpts from Behavioural biometrics: Online identification is getting more and more intrusive, Economist, May 23, 2019