Assentication: User Deauthentication and Lunchtime Attack Mitigation with Seated Posture Biometric.

Biometric techniques are often used as an extra security factor in authenticating human users. Numerous biometrics have been proposed and evaluated, each with its own set of benefits and pitfalls. Static biometrics (such as fingerprints) are geared for discrete operation, to identify users, which typically involves some user burden. Meanwhile, behavioral biometrics (such as keystroke dynamics) are well-suited for continuous and more unobtrusive operation. One important application domain for biometrics is de-authentication: a means of quickly detecting absence of a previously-authenticated user and immediately terminating that user’s secure sessions. De-authentication is crucial for mitigating so-called Lunchtime Attacks, whereby an insider adversary takes over an authenticated state of a careless user who leaves her computer.