A Lightweight Scheme for Securely and Reliably Locating SIP Users

1
A Lightweight Scheme for Securely and Reliably
Locating SIP Users

• Lei Kong
• Vijay A. Balasubramaniyan
• Mustaque Ahamad

2
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

3
SIP Trapezoid
4
Related Work

• SIPS
• DNS security extension
• Authentication Service
• Others

5
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

6
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

7
Initial Session Setup
8
Session Setup after Public Key Exchange
9
High Availability Via Replication

• Byzantine fault model
• Replication schemes
• For stateful proxy
• Consistency requirement
• For stateless proxy
• Optimistic assumption and parallel session setup

10
Stateful Example
11
Stateless Example
12
Preliminary Evaluation
13
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