This paper concerns the problem of phishing attacks in ubiquitous computing environments. The embedding of ubiquitous services into our everyday environments may make fake services seem plausible but it also enables us to authenticate them with respect to those environments. We propose physical and virtual linkage as two types of authenticating evidence in ubiquitous environments and two protocols based on them. We describe an experiment to test hypotheses concerning user responses to physical and virtual linkage with respect to fake Wi-Fi hotspots. Based on our experience we derive an improved protocol for authenticating spontaneously accessed ubiquitous services.

Users of public Wi-Fi networks risk being tricked into connecting to `evil twin' access points set up by attackers to launch man-in-the-middle attacks. We present a system which employs post hoc validation of an anonymous Diffie-Hellman key exchange undertaken as part of an 802.1X/EAP-TTLS network association process. Our system utilises an additional secure auxilliary channel to run a modified version of the interlock protocol based on physical evidence in the network location. By using keying information generated during the network joining process, we allow spontaneous network users to detect man-in-the-middle attacks as well as avoiding the need for pre-shared keys. We report on implementations of our system which utilise physical evidence of authenticity in the alternative forms of public displays and 2D barcodes embedded in the environment and read by mobile phones.

Pervasive systems provide services that are situated within specific contexts. An everyday example of this is Wi-Fi hotspots. Factors such as branding and presentation are known to affect whether users are prepared to invest trust in services, but little is known about trust in situated services. This paper describes an experiment to measure de facto trust in Wi-Fi hotspots in public places, as opposed to examining trust behaviour in a simulated lab setting. We investigated two hypotheses about the effect of location-specific images in the hotspot's pages on trust behaviours, compared to images of non-specific locations. We found a significant result which confirms that decisions to access an unfamiliar Wi-Fi hotspot can be affected by location-relevant images.

The use of location-based technology to augment visitor experiences has received considerable attention over the years. In this paper, we take an alternative perspective on these kinds of location-based experiences by focussing on the collecting and keeping of location-based content as opposed to simply the in situ consumption of content. We describe a trial of a location-based experience at London zoo in which mobile camera phones were used to access digital content at particular animal enclosures around the zoo. Through the fieldwork we demonstrate ways in which collecting and keeping have important social values over and above simply consuming the content in situ. More specifically, the role of the collection of location-based content in identity work; in developing a sense of challenge and achievement; in defining a sense of group camaraderie; and in creating a playful sense of competition among group members. Further, we see how narratives told around the collected location-based content over time imbue it with additional value. These narratives become part of the resources through which relationships with family and friends get actively constructed. We discuss how these aspects have different design implications from the in-situ consumption model of location-based experiences and tensions this introduces.

In this paper we describe an investigation into linkages to multimedia content from individual items in photographs and other printed images. We describe prototypes for authoring and playing such "active photos", and give the results of informal trials. We conclude with lessons learned and next steps.

This paper describes methods for service selection and service access for mobile, sensor-enhanced web clients such as wireless cameras or wireless PDAs with sensor devices attached. The clients announce their data-creating capabilities in "Produce" headers sent to servers; servers respond with forms that match these capabilities. Clients fill in these forms with sensor data as well as text or file data. The resultant system enables clients to access dynamically discovered services spontaneously, as their users engage in everyday nomadic activities.

We present an infrastructure for flexible and secure access to a group of distributed services in a nomadic computing environment, wherein users access local services from their mobile, wirelessly connected devices. We describe a secure hand-off' protocol, which allows a user to register with a single service that hands off' authorization to access a subset of the services. Our protocol helps maintain the user's privacy. It allows the services (which may be implemented on simple appliances) and the user's mobile device to have modest resources: services do not have to be online to any party except the user's device and the storage and communication requirements are minimal. In addition to the hand-off protocol, the paper presents a model for authorization hand-off and describes related research and technologies.

Identifier resolution is presented as a way to link the physical world with virtual Web resources. In this paradigm, designed to support nomadic users, the user employs a handheld, wirelessly connected, sensor-equipped device to read identifiers associated with physical entities. The identifiers are resolved into virtual resources or actions related to the physical entities - as though the user 'clicked on a physical hyperlink'. We have integrated identifier resolution with the Web so that it can be deployed as ubiquitously as the Web, in the infrastructure and on wirelessly connected handheld devices. We enable users to capture resolution services and applications as Web resources in their local context. We use the Web to invoke resolution services, with a model of 'physical' Web form-filling. We propose a scheme for binding identifiers to resources, to promote services and applications linking the physical and virtual worlds.

This paper reports on a study of clinicians who care for diabetic patients, and on the design of an application to support their work. The clinicians' long-term activity is rooted in a series of private sessions with the patient. Clinicians exchange information but the timeliness, specificity and other salient features of the communication are often unsatisfactory. Problems consequently arise such as the omission or duplication of tests. We describe a conceptual framework to account for the effectiveness of knowledge-sharing in groups such as these, and use it to motivate an application aimed at improving the clinicians' levels of communication and coordination.

No abstract available.