A Lightweight Scheme for Securely and Reliably Locating SIP Users Lei Kong Vijay A. Balasubramaniyan Mustaque Ahamad
Introduction Mapping SIP address to contact address is an important function in VOIP systems Key requirements: Integrity Availability Performance and scalability Our solution Lightweight scheme to meet these requirements
SIP Trapezoid
Related Work SIPS DNS security extension Authentication Service Others
Our Approach Proxies have certificates User contact address signed with locally generated public key SIP proxies protect user public key exchange Balancing between two extremes: PGP/SSH End user certificates Other SIP message fields can also be protected
Using SIP Infrastructure to Protect User Public Key Exchange Proxy awareness of user public keys User public key is registered with local proxies User public key is completely managed by end points
Initial Session Setup
Session Setup after Public Key Exchange
High Availability Via Replication Byzantine fault model Replication schemes For stateful proxy Consistency requirement For stateless proxy Optimistic assumption and parallel session setup
Stateful Example
Stateless Example
Preliminary Evaluation
Conclusions and Future Work Lightweight approach for securing contact address and other SIP message fields Availability with Byzantine failure Preliminary performance results show better scalability Future performance study and SIP extension RFC proposal