RE: SOI QUESTIONS: 2.4 Number of crypto operations

[Michael Thomas <mat@cisco.com>]

Stephane Beaulieu writes:
 > > Please discuss and answer this question.....
 > >
 > > 2.4 Number of crypto operations
 > >
 > > 2.4.A) JFK requires substantially more cryptographic operations for
 > > rekeying (two more signatures, two more signature validations, and
 > > three more hashes).  Is this a problem?  More generally, does SOI need
 > > to be able to support "fast" rekeying?
 > 
 > Yes.
 > 
 > To be more precise, SOI should have a 2 phases.  This will help with fast
 > rekeying, fast tunnel setup (for multiple tunnels), and better tunnel
 > management (this was the BIGGEST problem with IKEv1, IMO).

Perhaps a more sensible balance would be have the
initial exchange be able to produce a real IPsec
SA (ie self-contained), and be able to specify a
zero life for the SOI SA. That way, a compliant
implementation could choose not to implement
"quick mode" where there's no particular need.

I propose the following requirement:

"If SOI defines subsequent SOI exchanges derived
 by the shared state of an initial SOI exchange,
 the protocol MUST make these subsequent exchanges
 optional to both parties. A minimal SOI
 implementation MUST NOT be required to implement
 the subsequent exchanges."

		Mike