Subject: Using methods that derive keys

From: "Mohan Parthasarathy" <[email-masked]>
Date: Fri, 9 May 2003 14:18:21 -0700

Hello,

One of the requirements stated in the threats evaluation draft is :

PaC and PAA MUST mutually authenticate each other using methods that can derive
keys which in turn can protect success and failure indications.

In the light of the recent discussion and comments, it will be relaxed about when
success/failure can be protected. But there are other messages e.g. transmitting
the device identifier securely. This is done at the end and hence can be protected
if keys are derived.

The issue is that it assumes that a certain EAP method is used. Not all methods
can derive keys. So, we are indirectly mandating methods that derive keys. Is
that okay ? In the past discussions, we wanted to avoid this sort of thing. But
without extra protection, some of the attacks become possible now.

Comments ?

-mohan

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From: Alper Yegin <[email-masked]>
Date: Fri, 09 May 2003 18:00:31 -0700

> without extra protection, some of the attacks become possible now.

Key derivation, hence these type of EAP methods, are necessary only in some
environments, not all. So, we cannot generalize as PANA MUST be used only
when such methods are carried. Choice of authentication method is a
deployment issue. As long as PANA knows how to carry those methods, which it
already does as these are just EAP methods, it satisfies the requirement.

Those attacks which requires methods that generates keys are concern in
shared wireless scenarios. Not in physically secured, or already ciphered
link-layers (e.g., cdma2000).

Alper