WLC02-4: A Secure SIP-based Instant Messaging and Presence Framework for Ad-Hoc Networks

Various forms of ad-hoc networking are slowly emerging. However, a wider diffusion of ad-hoc networking in everyday life will only be possible if existing common middleware and applications are extended for use in ad-hoc networks. Many new Internet applications are based on sessions, e.g., instant messaging, VoIP and multimedia communications. The Session Initiation Protocol (SIP) is a popular protocol to manage sessions in IP networks. SIP is based on centralized servers, and application-level routing. SIP-based applications can not work in a distributed network of peer nodes, such as an ad-hoc network, due to the lack of the centralized servers. In this paper, we present a novel design that extends SIP for use in ad-hoc networks. Our enhancements allow existing applications to discover users within an ad-hoc network, make use of presence information, and set up VoIP and instant messaging sessions. These operations are performed in a secure way, as the framework provides integrity protection and verification of sender's authenticity. We discuss our software implementation of the scheme, and evaluate the performance, and applicability.