Subject: [eap] EAP SIM and EAP AKA status and key derivation

From: [email-masked] ([email-masked])
Date: Thu, 9 Jan 2003 16:25:25 +0200

Hello,

Here's a short status update on EAP SIM and EAP AKA.

We submitted to be draft-arkko-pppext-eap-aka-07.txt
and draft-haverinen-pppext-eap-sim-08.txt to the
RFC editor to be considered as informational RFCs.
However, based on comments from Bernard there
is a problem in the key derivation section and
some missing security claim considerations as required
by the latest RFC 2284bis that we need to fix, so we'll=20
have to revise the drafts and submit them again.

In short, the key derivation sections will be changed
so that we'll always generate the same amount of "application
specific keying" material (probably 192 bytes, just as in RFC 2716).
When RFC 2548 RADIUS key attributes are used to communicate=20
application keys then only the 64 bytes are needed, the first=20
32 bytes as the MS-MPPE-RECV-KEY and the second 32 bytes as the=20
MS-MPPE-SEND-KEY. Note that this is different from the=20
key derivation annexes of the current draft versions, where the=20
MS-MPPE-SEND-KEY is generated first when WEP is being used.

So the only technical change will be the order of the derived
application specific keys in the EAP SIM annex B and EAP AKA annex A
when WEP is used. For 802.11i, the PMK is still the first 32 bytes
from the application specific key stream. This change is needed=20
to make key distribution independent from ciphersuite.

Regards,
Henry