Re: about Wedgelayer 3.5 / Fat IP approaches

[marcelo bagnulo braun <marcelo@it.uc3m.es>]

> Next, I try to replace the current WIMP identifiers with NOID kind of 
> AIDs
> for both end-points; in the next WIMP I-D. The ephemeral context 
> identifiers together
> with hash chains would then be used only to identify the context. 
> Basically, they would
> serve the same purpose as the purpose built-keys for initiators.
> That is, epheral context identifiers could be used to prevent 
> attackers from stealing
> a context. (I'm trying to figure out how to bind a specific 
> application identifier to
> a specific context.)

I guess that we should see the details before commenting but in 
abstract terms, my concern would be:

In its current form WIMP uses:
- A hash of the FQDN as id of the receiver, and it uses the DNS to 
provide the required security. I mean, the mapping between the id and 
the FQDN is direct (id=hash(FQDN)). Next, the map between the FQDN and 
the locator set is provided by the DNS system (so you trust a third 
party to obtain such information) and so you know that if you send 
packets to those locators you are reaching the desired id.
- for the initiator, you use an ephemeral id. In this case, you don't 
need to worry about all the threats, since the ephemeral id won't be 
valid for following communications. Basically, the only thing you need 
to worry about is that the endpoint that is communicating remains the 
same. You don't worry about id hijacking since the id is ephemeral (so 
it will become meaningless in a short while)

Now, you are proposing to use long lived ids for the initiator as well. 
In this case, you solve the refferal problem, but the price is that you 
now have to consider all the threats that you were not considering when 
using ephemeral ids. So you need a mechanism to prove the initiator'r 
id ownership. In other words, imho hash chains are not enough in this 
case, and you need something else. NOID uses the DNS, HIP uses the 
crypto nature of its ids, what would be the mechanisms here for this?

> (snip)
>
> > what about cgas?
> > They are locators, so you can use them for refferals to non multi6 
> > apps and hosts, they allow to map from id to locators using reverse 
> > dns, and they are crypto in nature
> > seems a good candidate to me :-)
>
> That is one alternative. However, there are some IPR issues that must 
> be
> probably solved before applying cgas with multi6.

Yes, but those issues are being worked out in other wg, as in SeND, and 
imho we could be optimistics about this... (but my opinion on this 
matter is even more meaningless than in other topics, so...)

regards, marcelo

> > regards, marcelo
>
> br, Jukka