  The growing trend of using wearable devices for context-aware computing and
pervasive sensing systems has raised its potentials for quick and reliable
authentication techniques. Since personal writing habitats differ from each
other, it is possible to realize user authentication through writing. This is
of great significance as sensible information is easily collected by these
devices. This paper presents a novel user authentication system through
wrist-worn devices by analyzing the interaction behavior with users, which is
both accurate and efficient for future usage. The key feature of our approach
lies in using much more effective Savitzky-Golay filter and Dynamic Time
Wrapping method to obtain fine-grained writing metrics for user authentication.
These new metrics are relatively unique from person to person and independent
of the computing platform. Analyses are conducted on the wristband-interaction
data collected from 50 users with diversity in gender, age, and height.
Extensive experimental results show that the proposed approach can identify
users in a timely and accurate manner, with a false-negative rate of 1.78\%,
false-positive rate of 6.7\%, and Area Under ROC Curve of 0.983 . Additional
examination on robustness to various mimic attacks, tolerance to training data,
and comparisons to further analyze the applicability.
