Biblio

As our society massively relies on ICT, security services are becoming essential to protect users and entities involved. Amongst such services, non-repudiation provides evidences of actions, protects against their denial, and helps solving disputes between parties. For example, it prevents denial of past behaviors as having sent or received messages. Noteworthy, if the information flow is continuous, evidences should be produced for the entirety of the flow and not only at specific points. Further, non-repudiation should be guaranteed by mechanisms that do not reduce the usability of the system or application. To meet these challenges, in this paper, we propose two solutions for non-repudiation of remote services based on multi-biometric continuous authentication. We present an application scenario that discusses how users and service providers are protected with such solutions. We also discuss the technological readiness of biometrics for non-repudiation services: the outcome is that, under specific assumptions, it is actually ready.

Session management in distributed Internet services is traditionally based on username and password, explicit logouts and mechanisms of user session expiration using classic timeouts. Emerging biometric solutions allow substituting username and password with biometric data during session establishment, but in such an approach still a single verification is deemed sufficient, and the identity of a user is considered immutable during the entire session. Additionally, the length of the session timeout may impact on the usability of the service and consequent client satisfaction. This paper explores promising alternatives offered by applying biometrics in the management of sessions. A secure protocol is defined for perpetual authentication through continuous user verification. The protocol determines adaptive timeouts based on the quality, frequency and type of biometric data transparently acquired from the user. The functional behavior of the protocol is illustrated through Matlab simulations, while model-based quantitative analysis is carried out to assess the ability of the protocol to contrast security attacks exercised by different kinds of attackers. Finally, the current prototype for PCs and Android smartphones is discussed.