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Re: having and eating cake? agressive mode with identity hiding



  This is where some deployment experience comes in handy. In real
world situations-- outside bakeoffs-- there is rarely any negotiation.
Usually both sides are already configured and prepared to speak to 
each other. And in the rare cases in which they are not there are a
couple more messages to the exchange and possibly another exponentiation
in a new group, big deal. It seems better to optimize for the 
99%-of-the-time case.

  Dan.

On Tue, 14 Aug 2001 11:13:45 EDT you wrote
> Re: Sheila Frankel's pointing out the loss of ability to negotiate the D-H 
> group.
> 
> Is it that important to negotiate it rather than having Alice choose?
> If so, how many groups might Alice be willing to propose? If it's
> only a handful, then it wouldn't be tragic in the rare case where her choice
> was unacceptable to Bob for Bob to reply with "unacceptable D-H choice"
> and Alice to cycle through her choices. Or have Bob reply with his list of
> acceptable choices.
> 
> Radia
> 
> 
> 
> 	From: Sheila Frankel <sheila.frankel@nist.gov>
> 
> 	
> 	There is one problem that arises from adopting aggressive mode as the 
> single IKE
> 	variant. Since "g^a mod p" is sent in message 1, we lose the capability
> 
> to
> 	negotiate the Diffie-Hellman group.
> 	
> 	Sheila Frankel
> 	NIST
> 	
> 


References: