Subject: [eap] Proposed Resolution to Issue 273: Accept

From: Bernard Aboba <[email-masked]>
Date: Tue, 19 Oct 2004 12:28:59 -0700 (PDT)

The text of Issue 273 is enclosed below.  The proposed resolution is as
follows:

Change the definition of PMK to the following:

   PMK Name

     This document does not specify any naming scheme for the PMK.
     The PMK is only identified by the AAA-Key from which it is
     derived.

     Note: IEEE 802.11i names the PMKID for the purposes
     of being able to refer to it in the Secure Association
     protocol; this naming is based on a hash of the PMK itself
     as well as some other parameters (see Section 8.5.1.2 [ref]).

----------------------------------------------------------------------
Issue 273: PMK Naming
Submitter name: Florent Bersani
Submitter email address: [email-masked]
Date first submitted: 10/4/2004
Reference: http://mail.frascone.com/pipermail/eap/2004-October/002848.html
Document: Keying-03
Comment type: E
Priority: 1
Section: 2.4 and 3.4.1
Rationale/Explanation of issue
I find the following confusing. In section 2.4, I read

"PMK Name

       The PMK has no name of its own, and is only identified by the AAA-
       Key from which it is derived."

but in Section 3.4.1, I find "PMKID (security association
identifier)"... so it seems to me that the PMK has no name but has an
identifier (defined in clause 8.5.1.2 of IEEE 802.11i IIRC). I guess it
could be worth clarifying this subtlety, wouldn't it?

Requested change

Would our 802.11i experts approve the following:
"PMK Name

       The PMK may be named by its identifier PMKID defined in clause
8.5.1.2 of [IEEE80211i]."
[Jari Arkko]
I agree that the current text is confusing. On the other hand,
there's a distinction between what the keying framework documents
and what additional things may be done by link layers.
[Florent Bersani]
OK  but my understanding is that the PMK is bound to a specific link
layer, namely IEEE 802.11i

(see e.g. section 2.1: "Pairwise Master Key (PMK)
     The AAA-Key is divided into two halves, the "Peer to Authenticator
     Encryption Key" (Enc-RECV-Key) and "Authenticator to Peer
     Encryption Key" (Enc-SEND-Key) (reception is defined from the point
     of view of the authenticator).  Within [IEEE80211i] Octets 0-31 of
     the AAA-Key (Enc-RECV-Key) are known as the Pairwise Master Key
     (PMK).  In [IEEE80211i] the TKIP and AES CCMP ciphersuites derive
     their Transient Session Keys (TSKs) solely from the PMK, whereas
     the WEP ciphersuite as noted in [RFC3580], derives its TSKs from
     both halves of the AAA-Key.")

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