Subject: RE: [eap] Issue: Use of term lower layer

From: "Salowey, Joe" <[email-masked]>
Date: Wed, 7 Dec 2005 09:01:39 -0800

> 
> >---
> >Change
> >
> >"EAP keying material and parameters provided to a lower layer other
> >   than AAA MUST NOT be transported to another entity."
> >
> >To
> >
> >"EAP keying material and parameters provided to a lower 
> layer MUST NOT 
> >be transported to another entity."
> >  
> >
> Seems to prohibit distributed authenticators, including 
> 802.11r. I'd be OK with this if we didn't exclude 
> transportation of keys derived from the provided keys.
>
[Joe] OK, but I think the original text would cause problems with .11r
as well.  In any case I'm OK with the lower layer doing what ever it
wants with the keys once it has them.  I think what we want to avoid is
the same keys and parameters being sent to more than one lower
layer/application. 

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---

From: Jari Arkko <[email-masked]>
Date: Tue, 13 Dec 2005 15:37:02 +0200

Joe,

>the same keys and parameters being sent to more than one lower
Agreed. How about this:

"In order to preserve the security of keys derived within EAP methods,
lower layers other than AAA MUST NOT export keys passed down by EAP
methods. This implies that EAP keying material or parameters passed
down to a lower layer are for the exclusive use of that lower layer
and MUST NOT be used within another lower layer. This prevents
compromise of one lower layer from compromising other applications
using EAP keying parameters.

EAP keying material and parameters provided to a lower layer other
than AAA MUST NOT be transported to another entity. For example, EAP
keying material and parameters passed down to the EAP peer lower
layer MUST NOT leave the peer; EAP keying material and parameters
passed down or transported to the EAP authenticator lower layer MUST
NOT leave the authenticator."

to

"In order to preserve the security of keys derived within EAP methods,
EAP keying material or parameters passed down to a lower layer
are for the exclusive use of that lower layer. This prevents
compromise of one lower layer from compromising other applications
using EAP keying parameters.

EAP keying material and parameters provided to a lower layer
MUST NOT be transported to another entity. The same applies
to other keying material derived from the EAP keying material, if
the EAP keying material can be computed from the other material
without breaking some cryptographic assumption, such as inverting
a one-way function. For example, MSK passed down to the EAP peer lower
layer or transported to the authenticator MUST NOT leave the peer. "

--Jari