Subject: [eap] Proposed Resolution to Issue 314: AAA-Key Confusion

From: "Bernard Aboba" <[email-masked]>
Date: Sun, 08 Jan 2006 10:31:05 -0800

The text of Issue 314 is available here:
http://www.drizzle.com/~aboba/EAP/eapissues3.html#Issue%20314

The Proposed Resolution is as follows:

In Section 1.2, change:

"AAA-Key
     A key derived by the peer and EAP server, used by the peer and
     authenticator in the derivation of Transient Session Keys (TSKs).
     Where a backend authentication server is present, the AAA-Key is
     transported from the backend authentication server to the
     authenticator.  In existing usage, the AAA-Key is always derived
     from the MSK and so can be referred to using the MSK name.  AAA-Key
     = MSK(0,63)."

To:

"AAA-Key
The term "AAA-Key" is synonymous with MSK."

In Section 2.1, change:

"  An additional step (phase 1b) is required in deployments which
  include a backend authentication server, in order to transport keying
  material from the backend authentication server to the authenticator.
  In order to obey the principle of Mode Independence, where a backend
  server is present AAA Key transport needs to provide the exported EAP
  keying material and/or derived keys required for derivation of the
  TSKs.  Since existing TSK derivation techniques depend solely on the
  MSK, in existing AAA implementations, this is the only keying
  material replicated in the AAA key transport phase 1b. "

To:

" An additional step (phase 1b) is required in deployments which
  include a backend authentication server, in order to transport keying
  material from the backend authentication server to the authenticator.
  In order to obey the principle of Mode Independence, where a backend
  server is present, all keying material which us required by the lower 
layer needs to
  be transported from the EAP server to the authenticator.
  Since existing TSK derivation techniques depend solely on the
  MSK, in existing implementations, this is the only keying
  material replicated in the AAA key transport phase 1b. "

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From: Jari Arkko <[email-masked]>
Date: Wed, 11 Jan 2006 12:21:45 +0200

Looks ok. s/us/is/

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From: Yoshihiro Ohba <[email-masked]>
Date: Wed, 11 Jan 2006 08:59:55 -0500

> The term "AAA-Key" is synonymous with MSK."

This does not work for draft-ohba-eap-aaakey-binding-01 where 
AAA-Key = KDF(MSK, AAA-Key-name|key-binding-blob).

Yoshihiro Ohba