eap Mailing List: Re: Issue on eap-keying: PMK naming

[Florent Bersani (florent.bersani]

Jari Arkko wrote:

> Florent Bersani wrote:
>
> >    Description of issue: possible confusion between PMK naming and PMKID
> >
> >    Submitter name: Florent Bersani
> >
> >    Submitter email address: florent.bersani [at] francetelecom.com
> >
> >    Date first submitted: 10/04/2004
> >
> >    Document: Keying Framework
> >
> >    Comment type: 'E'ditorial
> >
> >    Priority: '1' Should fix
> >
> >    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]."
>
>
> 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.

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.")

> Here's
> a slightly modified text suggestion:
>
>   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]).

I guess I understand that the "names" that eap-keying defines are the 
ones to be included in the document, hence, since it is 802.11i which 
defines the PMK "name", this name has not its place in the document.

Perhaps sth like what's writtent about the TEKs, i.e., "the PMK naming 
is specified in IEEE 802.11i" would do just fine but the text jari 
proposes is OK for me,  although I am not sure what "naming the PMKID 
means". Wouldn't "IEEE 802.11i names the PMK thanks to a PMKID..." be 
better?

> --Jari