A secure voip conference system: architecture analysis and design issues

ABSTRACT

In this paper we present the architectural design of a secure VoIP conference system for mobile devices, which is using the strong security mechanisms of the Z Real Time Transport Protocol (ZRTP). We also provide implementation fundamentals of the proposed system. We analyze the core elements and we present the primitive characteristics of the component applications. Our approach follows the Client-Server model for packet relaying and subsidiary procedures like user sign-in and the direct client connection model for key exchange between the users. Experimental results regarding the performance of our prototype show that the processor overhead and the time delay are low, while the system scales well for more than 6 participants in real world conditions.

REFERENCES

• 1: http://www.ethereal.com
• 2: http://vomit.xtdnet.nl
• 3: http://wiki.ethereal.com/rtpdump
• 4: H. Schulzrirnne et al, "RTP: A Transport Protocol for Real-Time Applications", RFC 1889
• 5: M. Baugher , D. McGrew , M. Naslund , E. Carrara , K. Norrman, The Secure Real-time Transport Protocol (SRTP), RFC Editor, 2004
• 6: Phil Zimmerman, Alan Jonston and Jon Callas, "ZRTP: Extensions to RTP for Diffie-Hellman Key Agreement for SRTP", Internet Draft
• 7: Bruce Schneier, Description of a New Variable-Length Key, 64-bit Block Cipher (Blowfish), Fast Software Encryption, Cambridge Security Workshop, p.191-204, December 09-11, 1993
• 8: http://en.wikipedia.org/wiki/G.711
• 9: http://en.wikipedia.org/wiki/Diffie-Hellman

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.4 INFORMATION SYSTEMS APPLICATIONS
      H.4.3 Communications Applications
          Subjects: Computer conferencing, teleconferencing, and videoconferencing

General Terms:
Design, Experimentation, Performance, Security

Keywords:
VoIP, conference, real-time communications, security