[chair hat off]

Valery Smyslov writes:
> I think it is a bit early to discuss particular approaches,
> before the WG makes a decision to adopt the document.

Yes and no.

It is too early to think about actual protocol decisions, but we need
to know whether current draft is suitable for protocol selections we
are going to be doing, and we need to think about what kind of
compromizes we want to do.

I.e., I think it is important to think even in this phase, whether we
care about the identity hiding against passive attackers who can break
Diffie-Hellman or not. And do we care about identity protection
against active attackers. If we do want to protect against one of
those kinds of attackers, our solutions are going to be more
complicated.

If we do not care (i.e., keep the current level of protection in IKEv2
meaning no identity protection against active attackers or attackers
who can break Diffie-Hellman) then our solutions are simplier.

These requirements and compromizes are the important things we need to
decide on the WG before we can make decisions on the actual protocol
solutions. 

> Not necessary. In particular, the current draft allows to detect 
> OOB key mismatch and to act gracefully in this situation.
> And I don't think it is far too complicated.

Current draft does, but there has been other proposals which did not.

The current draft is also very costly and allows very easy denial of
service attacks, as responder needs to linear search of all possible
configured PPKs. If we for example use some kind of one time password
system, where each user has 1000 pre-distributed PPKs and we have 1000
users, responder needs to do million operations every time someone
sends him a packet or same thing if we have million users configured
and each have one PPK. Thats why I do not like the current approach
and I think trying to hide the identity for the active attacker is
just opening other attacks which are worse than the attack where
attactive attacker can learn the ID of the initiator...

Anyways I think we should work on this problem, and I think we do want
to think about the requirements for the solution we are going to do
before we can start writing actual protocol specification. And the
protocol specification can be based on either one of the drafts, there
is not that big difference in them, and depending on the requirements
things needs to be added or removed from the drafts.
-- 
[email protected]

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