[VOIPSEC] Actual Attacks

[Robert Moskowitz]

At 03:31 AM 2/26/2005, Simon Horne wrote:

>With reference to the above product, more than ever vendors have to 
>seriously consider Media Encryption with a Handshake technique which foils 
>these types of "wire taps".

What is Media in this comment?  802 media?  SONNET, ATM, etc media?

>Methods such as Single Use Diffie Hellman generated half key pairs (with 1 
>half encrypted) as used in TLS on a seperate secure channel is an 
>excellent method to stop the "Man in the Middle" from being able to 
>decrypt the voice traffic. They may be able to capture to .wav the 
>contents of the conversation but it would be complete garbage. Each 
>conversation or part of conversations are encrypted differently so the 
>'tapper' has to use repeated blunt force attacks to access the entire 
>conversation. If a large Diffie Hellman "Prime" length is used (> 
>1536bits) and a high quality cipher (say AES256), makes it almost 
>impossible for all but the the most serious 'tapper' to access.



Robert Moskowitz
Senior Technical Director
ICSA Labs, a division of Cybertrust, Inc.
W:      248-968-9809
F:      248-968-2824
E:      rgm at icsalabs.com

There's no limit to what can be accomplished
if it doesn't matter who gets the credit