Re: gs2 hashed oids

[Arnt Gulbrandsen <[e-mail]>]

Jeffrey Hutzelman writes:
> Stackable pseudo-mechanisms are not the same as multi-level negotiation.
> Multi-level negotiation is a problem because you end up having to 
> agree on one level before knowing if there's a mutually-acceptable 
> mechanism at the next.  But stackable mechanisms don't work that way; 
> every possible stack has an OID, composed from the OID's of the 
> stacked mechanisms (see section 4.1 of 
> draft-ietf-kitten-stackable-pseudo-mechs-02.txt).  Then the entire 
> _stack_ is negotiated at once, as if it were a single mechanism.  
> This leads to an explosion of possible mechanism OID's, where it's 
> not entirely possible to predict what they all are, but is entirely 
> unreasonable to expect every combination to be named and registered.

It sounds as though a server asked to use GS2-GQGFDSAGDSAF would have to 
recurse through all possible mechanism stack, encoding its OID as 
described in the kitten draft, hashing the resulting OID and comparing 
it against the desired name. Have I understood it correctly? (If not, 
then maybe it's nonobvious and should be explained in the GS2 
document.) If I have, then is that practical to recurse through the 
tree to find the mechanism?

Arnt