Dynamic sample size detection in continuous authentication using sequential sampling

Continuous Authentication (CA) departs from the traditional static authentication scheme by requiring the authentication process to occur multiple times throughout the entire logon session. One of the main objectives of the CA process is to detect session hijacking. An important requirement about designing or operating a CA system is the need to achieve the quickest detection while maintaining rates of missed and false detections to predetermined levels. We introduce in this paper a new approach for detection based on the sequential sampling theory that allows balancing appropriately between detection promptness and accuracy in CA systems. We study and illustrate the proposed approach using an existing mouse dynamics biometrics recognition model and corresponding sample experimental data.