End-to-End Voice Encryption over GSM: A Different Approach

Presented at DEF CON 13 (2005), July 29, 2005, 11 a.m. (50 minutes)

Where is end-to-end voice privacy over cellular?  What efforts are underway to bring this necessity to the consumer?  This discussion will distill for you the options available today, and focus on current research directions in technologies for the near future. Cellular encryption products today make use of either circuit switched data (CSD), or high latency packet switched networks.  We will discuss the advantages and disadvantages of these services, focusing on details of GSM cellular channels specifically.  The highlight will be our current research project: encrypted voice over the GSM voice channel.  We'll dig into how this works, and why it is useful. This talk will touch on some fundamentals of modem design, voice codecs, GSM protocol basics, cryptographic protocols for voice links, and a bunch of other interesting stuff.  There will be demonstrations with MATLAB/Octave and C, and we will provide some fun code to experiment with.


  • Nick Lane-Smith
    Nick is a security engineer at an innovative computer company in Cupertino, California. He holds a B.S. in Computer Science from the University of California, Santa Barbara and as far as I know, he is through with the school thing. He is currently unreachable in Antigua, so I suppose I could say anything here. I won't.
  • Wesley Tanner
    Wes is a systems engineer at a software-defined radio company in San Diego, California. He holds a B.S. in Electrical Engineering from Rensselaer Polytechnic Institute and is thinking of returning to school to formally study communication systems.


Similar Presentations: