FingerPattern: Securing Pattern Lock via Fingerprint-Dependent Friction Sound

Pattern lock is widely used for user authentication in mobile devices due to its simplicity and ease of remembering. However, it is vulnerable to various attacks, e.g., shoulder surfing attacks. In this paper, we propose FingerPattern, a novel enhanced pattern lock authentication system by using friction sound as a second authentication factor. When the user inputs the pattern by swiping his/her fingertip on the screen, the friction sound is generated based on the user's fingerprint and is unique. Thus, FingerPattern can identify and rule out the illegality by utilizing fingerprint-dependent friction sound even if the adversary has inferred the pattern. By this method, FingerPattern secures pattern lock without the need for a change in user unlocking habits. Extensive experiments demonstrate that FingerPattern can identify legitimate users with 97.5% TAR in one attempt and defend against various attacks (e.g., only 16.8% FAR in five attempts even if the adversary can clearly spy on the user's unlocking process). FingerPattern can be incorporated into the existing pattern lock of mobile devices, which is cost-free. Furthermore, a user experience study shows that FingerPattern is well-received by users.