• Ahmed, Naveed
• Jensen, Christian Damsgaard

Abstract

Security and usability are often horn locked and system administrators tend to configure systems so thatthey favor security over usability. In many cases, however, the increased security results in usability that is sopoor that users feel the need to circumvent the security mechanisms. This is probably best explained byconsidering password based authentication, where a user is actively involved in the process. If the timerequiredtologintoanaccountisconsideredtoohigh,userstendtoleavetheirterminalsloggedinthroughout the day and share their account with other users. This is particularly true for nomadic users whomove around in ubiquitous computing environments and avail from different IT services from many differentlocations. In many ubiquitous computing environments, where information processing is not considered themain priority, managementoften accepts thispractisein order to increaseproductivity, e.g., in ahectichospital environment, medical staff has to login and logout of various machines several timesin an hour, butthe repeated interactions consume a considerable amount of time, causing organizational inefficiency, jobfrustration and a tendency towards defeating the obstacle by leaving terminals logged in or choosing shortand easy to type passwords. Therefore, a password based authentication mechanism, which is quite simpleand secure in personal computing, has become too cumbersome for nomadic users, which means that othermeans of authentication must be developed for nomadic users.Inthispaper,wefocusonusabilityofauthenticationfornomadicusersinaubiquitouscomputingenvironment. We identify requirements for authentication of nomadic users and propose an authenticationframework for this class of users. A prototype of the proposed authentication framework has been developed,which supports persistent and multi­factor authentication without the active intervention of a user.We evaluate the usability of the developed mechanism by considering the time required to authenticatewhen logging in to a workstation and compare this to classic password based authentication. The evaluationshows that the proposed mechanism saves a significant amount of time for the nomadic users, which reducesthe incentive to circumvent the authentication mechanism. Thus, the mechanism will both provide users withbetter job satisfaction and increased organizational efficiency, while at the same time increase the effectivelevel of security of the system.

Topics

• impedance spectroscopy