Continuous Authentication using Biometric Keystroke Dynamics

When talking about authentication in general and biometrics in particular, we envisage a situation where a user provides an identity and gives proof of this identity, in order to get access to certain services. This kind of authentication (called static authentication) is done when rst accessing a service and will be valid throughout a full session, until the user logs o from that session. Most authentication methods are very well suited for this kind of (static) authentication, e.g. the well known username/password combination for access to computers or websites. In this article we will discuss a dierent kind of authentication, which will be applied after the start of a session, and will monitor if the current user is the same as the user who performed the initial static authentication. This new type of authentication is called dynamic authentication or continuous authentication. We will in particular look at sessions at a computer where we monitor the typing behavior of the user to detect anomalies. Normal techniques used in biometrics cannot be applied anymore. We will explain the dierences between