TwistIn

Abstract

Smart devices contain sensitive information that has to be guarded against unauthorized access through authentication. Existing authentication methods become obsolete as they are designed either for logging-in one device at a time or are ineffective in a multi-user multi-device environment. This paper presents TwistIn, a simple gesture that takes a smartwatch as an authentication token for fast access and control of other smart devices. Our mechanism is particularly useful for devices such as smartphones, smart glasses, and small IoT objects. To log in a device, one simply need to pick it up and twist it a few times. Then, by co-analyzing the motion data from the device and the watch, our method can extend the user authentication on the watch to the device. This is a simple and tangible interaction that takes only one to two seconds to perform. Furthermore, to account for user variation in wrist bending, we decompose wrist and forearm rotations via an optimization to improve the method accuracy. We implemented TwistIn, collected thousands of gesture samples, and conducted various experiments to evaluate our prototype system and show that it achieved over 95% detection accuracy.