In pervasive computing environments, powerful handheld devices with wireless connections create opportunities for many new nomadic applications. We propose a new service discovery model, called Splendor, supporting nomadic users and services in public environments. Splendor emphasizes security and supports privacy. Location awareness is integrated for location dependent services discovery and is used to lessen service discovery network infrastructure requirements. We analyze the Splendor system performance and provide our experimental results. 1.

Service Discovery as an essential element in pervasive computing environments is widely accepted. Much research on service discovery has been conducted, but privacy and security have been ignored and may be sacrificed. While it is essential that legitimate users should be able to discover services, it is also necessary that services be hidden from illegitimate users. Since service information, service provider’s information, service requests, user presence information, and user’s identities may be sensitive, we may want to keep them private during service discovery processes. There appears to be no existing service discovery protocols that solve these problems. We present a user-centric model, called PrudentExposure, which exposes minimal information privately and securely. Users and service owners exchange code words in an efficient and scalable form to establish mutual trust. Based on the trust, secure service discovery sessions are set up. The model is further improved to counter attacks. We analyze the mathematical properties of our model, formally verify our security protocol, and measure the performance of our prototype system.

This paper surveys research in service advertising, discovery and selection for mobile ad hoc networks (MANETs) and related issues. We include a categorization of service discovery architectures for MANETs and their modes of operation, presenting their merits and drawbacks. We pay particular attention to cross-layer service discovery a special class of efficient service discovery approaches for MANETs. We also present security issues and discuss service description options, service selection mechanisms and service state maintenance techniques. We conclude with a summary, an outlook and directions for future research in this area.

Abstract. Most of today’s authentication schemes involve verifying the identity of a principal in some way. This process is commonly known as entity authentication. In emerging ubiquitous computing paradigms which are highly dynamic and mobile in nature, entity authentication may not be sufficient or even appropriate, especially if a principal’s privacy is to be protected. In order to preserve privacy, other attributes (e.g. location or trustworthiness) of the principal may need to be authenticated to a verifier. In this paper we propose Ninja: a non-identity-based authentication scheme for a mobile ubiquitous environment, in which the trustworthiness of a user’s device is authenticated anonymously to a remote Service Provider (verifier), during the service discovery process. We show how this can be achieved using Trusted Computing functionality.

Securely accessing unfamiliar services in public environments using ad hoc wireless networks is challenging. We present a proxy-based approach that uses other existing network channels to set up a secure and trust relationship between communication parties to facilitate ad hoc wireless communications. Based on a service discovery protocol, our models achieve secure, trusted, anonymous, efficient, and economical communications between unfamiliar parties. Our protocols are formally verified using BAN logic. 1.

Abstract. The computing and networking capacities of today’s wireless portable devices allow for pervasive services, which are seamlessly networked. Indeed, wireless handheld devices now embed the necessary resources to act as both service clients and providers. However, the seamless networking of services remains challenged by the inherent mobility and resource constraints of devices, which make services a priori highly volatile. This paper discusses the design, implementation and experimentation of the ubiSOAP service-oriented middleware, which leverages wireless networking capacities to effectively enable the seamless networking of services. ubiSOAP specifically defines a layered communication middleware that underlies standard SOAP-based middleware, hence supporting legacy services while exploiting nowadays pervasive connectivity. 1

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Pervasive environments are characterized by rich and dynamic context, where users need to be continuously informed about services relevant to their current context. Implicit discovery requests, triggered by changes of user context, available services, or user preferences are prevalent in such environments. This paper proposes a proactive service discovery approach for pervasive environments to address these implicit requests. Services and user preferences are described by a formal context model, which effectively captures the dynamics of context and the relationship between services and users. Based on the model, we propose a proactive discovery algorithm to continuously present the most relevant services to the user in response to changes of context, services or user preferences. Numeric coding methods are applied in different phases of the algorithm to improve its performance. A proactive service discovery system is proposed and the context model is grounded in a smart home environment. Experimental results show that our approach can efficiently provide the user with up-to-date information about useful services.

In pervasive computing environments, service discovery facilitates users to access network services by automating tedious manual configurations. When network services becomes pervasive, the number of service providers also increase dramatically. Because of security and privacy concerns, network services are segmented by service providers. Existing service discovery protocols, however, do not address how to facilitate users to properly identify and authenticate with existing service providers. Without prudence, sensitive information may be exposed. Conversely, with prudence both users and service providers prefer the other party to expose sensitive information first. We identify that even among legitimate users and service providers, there are privacy concerns that may be expressed as a chicken-and-egg problem. In this paper, we propose a progressive approach to solve the problem. Users and service providers expose minimal sensitive information in turn and identify necessary exposure during the process. Theoretical analysis, simulation, and experiments show that our approach protects sensitive information with little overhead.

Abstract. This chapter deals with interoperability among pervasive networked systems, in particular accounting for the heterogeneity of protocols from the application down to the middleware layer, which is mandatory for today’s and even more for tomorrow’s open and highly heterogeneous networks. The chapter then surveys existing approaches to middleware interoperability, further providing a formal specification so as to allow for rigorous characterization and assessment. In general, existing approaches fail to address interoperability required by today’s ubiquitous and heterogeneous networking environments where interaction protocols run by networked systems need to be mediated at both application and middleware layers. To meet such a goal, this chapter introduces the approach that is investigated within the Connect project and that deals with the dynamic synthesis of emergent connectors that mediate the interaction protocols executed by the networked systems.