eap Mailing List: RE: Re: Issue 362: Lower layer parameters and EMSK text

[Nakhjiri Madjid-MNAKHJI1 (Madjid.Nakhjiri]

-----Original Message-----
From: Bernard Aboba [mailto:bernard_aboba [at] hotmail.com] 
Sent: Monday, May 08, 2006 9:33 AM
To: eap [at] frascone.com
Subject: [eap] Re: Issue 362: Lower layer parameters and EMSK text

Move the following text from Section 2 to Section 1.4:

"The EMSK MUST NOT be provided to an entity outside the EAP server or
peer, nor is it permitted to pass any quantity to an entity outside
the EAP server or peer from which the EMSK could be computed without
breaking some cryptographic assumption, such as inverting a one-way
function. As noted in [RFC3748] Section 7.10:

   The EMSK is reserved for future use and MUST remain on the EAP
   peer and EAP server where it is derived; it MUST NOT be
   transported to, or shared with, additional parties, or used to
   derive any other keys."


Madjid>>Why do we prohibit use of EMSK in deriving other keys? I was
under the assumption that it was the intention to leave to specification
of EAP keying fwk extensions, such as derivation of AMSK to future
activities. The current text prohibits any such derivation. Is this the
intent?

"prohibiting" something is different from saying "it will be defined
later".

Why can't we replace the last phrase with:

"The Use of EMSK in deriving any other keys will be part of future
specifications"?

Thanks,

Madjid