Cullen Jennings

SOSIMPLE: A Serverless, Standards-based, P2P SIP Communication System

Voice over IP (VoIP) and instant messaging (IM) systems to date have either followed a client-server model or have required the use of clients that do not follow any VoIP or IM standard. We present SOSIMPLE - a fully decentralized, P2P, standards-based approach to communications. By building on the existing SIP/SIMPLE infrastructure for VoIP and IM, we support reuse of clients, network infrastructure, and open-source protocol stacks designed using current standards. By avoiding traditional centralized architectures, SOSIMPLE addresses corporate privacy concerns, eliminates dependency on constant Internet connectivity, and supports ad hoc groups. SOSIMPLE implements a DHT overlay based on Chord (Stoicha et al., 2001) using SIP messages, replicating location information for reliability. The DHT is used only for lookups, with actual communication passing directly between clients. We discuss important issues for security and authentication, as well as adaptations of conventional P2P routing for the social networks typical of personal communications. We are testing a prototype implementation of SOSIMPLE and anticipate a public release in the near future

Real-time communications for the web

This article provides an overview of the work that W3C and IETF are doing toward defining a framework, protocols, and application programming interfaces that will provide real-time interactive voice, video, and data in web browsers and other applications. The article explains how media and data will flow in a peer-to-peer style directly between two web browsers. This explains the protocols used to transport and secure the encrypted media, traverse NATs and firewalls, negotiate media capabilities, and provide identity for the media.

Providing response identity and authentication in IP telephony

The traditional circuit switched infrastructure for telephony services are being replaced by voice over IP (VoIP) for many forthcoming benefits. At the same time, there are some new security issues due to the introduction of new packet switched infrastructure and new VoIP protocols. One of crucial security issues faced by the current VoIP protocols is about the end-to-end user identity and how to authenticate it. This is especially important for guaranteeing integrity and privacy of the response information, because the current proposal solutions fail in many real-world scenarios. In this study, we demonstrate one new mechanism for providing and authenticating response identify, based on Session Initiation Protocol (SIP). In order to prevent several kinds of malicious attacks through response and protect the integrity of response message, another new per-hop authentication mechanism was proposed to handle SIP response. With the combination of these proposed mechanisms, response identity can be securely provided, and spam IP telephony (SPIT) or other malicious attacks can be identified and prevented from attacking the VoIP service.