A Peer-to-Peer Secure VoIP Architecture

Abstract

Voice over IP (VoIP) and multimedia real-time communications between two or more parties are widely used over the Internet. The Session Initiation Protocol (SIP) is the current signaling standard for such applications and allows users to establish and negotiate any end-to-end multimedia session. Unfortunately current SIP-based platforms use a centralized architecture where calls between User Agents (UAs) are routed based on static public-reachable proxy servers, suffering of well-known scalability and availability problems. Moreover, security is currently poorly implemented and, when supported, it usually relies on a third-party trust relationship or on a Public Key Infrastructure (PKI). In this work we propose a completely distributed P2P VoIP architecture where calls are routed relying on a Location Service implemented through a Distributed Hash Table (DHT). End-to-end security is also provided without the use of any centralized server or PKI. Secure media sessions are established and authenticated on the basis of previously established sessions or by simple peer’s voice recognition. The proposed architecture has been also implemented and publicly released.