Re: [SIP] Re: SIP gateways and authentication

[Michael Thomas]

James A. Donald writes:
 > In all public key solutions, 
 > the public keys are used to set up a symmetric key that is not subject to 
 > dictionary attacks.

   False. A public key solution that chose bad
   symmetric keys would be subject to dictionary
   attacks and much more.

 > It is probably possible to set up a system with properties similar to those 
 > that I outlined using nothing but symmetric key cryptography, though it 
 > would be more complex, hence harder to
 > understand and harder to get right.

   FSVO "more".
 
 > Existing symmetric key solutions (Kerberos) are vulnerable to
 > dictionary attack

   This is a ludicrous strawman. People choose
   dictionary attackable symmetric keys, not
   Kerberos. 

   Talk about babies and bathwater...

                Mike