Subject: [eap] Comments on Section 1.2 of draft-ietf-eap-keying-18.txt

From: "Glen Zorn (gwz)" <[email-masked]>
Date: Sun, 4 Mar 2007 01:22:03 -0800

I apologize for the tardiness of these comments: I planned to send this
email over a week ago but I experienced some computer issues ;-).

The definitions of both "authenticator" and "peer" refer to these as
'end of the link'; this seems just a bit too vague to me (after all,
what's at the "end of a link" is usually a transceiver, right, which is
generally neither an authenticator nor a peer ;-): I would prefer to see
them referred to at least as entities. For example:

"authenticator
     The entity initiating EAP authentication..."
&
"peer
     The entity that responds to the authenticator."

Although this change clarifies slightly the nature of the EAP peer and
authenticator, it may require the rethinking of some other definitions.
For example, see the definition of "Secure Association Protocol" later
in this section: only if "peer" & "authenticator" are defined in the
original (vague) manner can this definition be accurate, since the
entities involved in the 802.11i 4-way handshake are, I think, quite
different from the EAP entities.  In general, the consumers/users of the
keys that may be generated as a side-effect of EAP authentication are
not identical to the EAP entities, however, a fact that seems to be if
not lost then at least glossed over in this document.  Further  examples
can be found in the definitions of "Transient EAP Keys (TEKs)", where
the EAP peers are presumed to continue sending & receiving encrypted
data after authentication is complete(!) and "Transient Session Keys
(TSKs)", where the EAP peers negotiate a ciphersuite for this purpose.
Although I don't think it's prohibited for EAP methods to negotiate
ciphersuites for subsequent use _by other protocols_ (such as 802.11i,
etc.), I don't know of any that do & I don't think that that is what is
meant in this definition: it is only the rather IMHO sloppy use of the
terms "authenticator" and "peer" to mean, basically, "whatever is
hanging off the ends of the wire" that allows this usage.

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