PRISM: Policy-driven Risk-based Implicit locking for improving the Security of Mobile end-user devices

Nowadays, most mobile applications rely on device screen locking mechanisms for ensuring practical security, which expects the users to explicitly authenticate with a PIN or biometric irrespective of the perceived threats. Owing to this usability issues, many avoid using device locks potentially compromising the security. To overcome the limitations of this binary approach, we present an implicit authentication framework called PRISM (Policy-driven Risk-based Implicit locking for improving the Security of Mobile end-user devices). It provides risk based authentication by detecting anomalies in the usual behavior patterns of the users which include their expected locations, activities and application usage. Its device unlocking decisions are driven by policies that are defined either automatically by mining sensor data or manually by the end-users. Our experiments show that PRISM is able to discover useful behavior patterns efficiently even with limited data. The number of required explicit authentications is significantly reduced while assuring the preferred security for everyday scenarios.