Subject: [Pana] pana-fwk technical issue 1/4

From: Yoshihiro Ohba <[email-masked]>
Date: Thu, 16 Dec 2004 16:52:12 -0500

Issue: How PMK for each AP is obtained by PaC?

Proposed resolution is to add text mentioning that PMK is derived from
AAA-Key in the following way.

Change the first paragraph of section 10.2.2:

"
   In this model, PANA is used for authentication and authorization, and
   L2 ciphering is used for access control, the latter is enabled by the
   former.  The L2 ciphering is based on using PSK (Pre-Shared Key) mode
   of WPA (Wi-Fi Protected Access) [WPA] or IEEE 802.11i [802.11i],
   which is derived from the EAP MSK as a result of successful PANA
   authentication.  In this document, the pre-shared key shared between
   station and AP is referred to as PMK (Pair-wise Master Key).  In this
   model, MAC address is used as the device identifier in PANA.
"

to:

"
   In this model, PANA is used for authentication and authorization, and
   link-layer ciphering is used for access control.  Successful PANA
   authentication enables link-layer ciphering which is based on PSK
   (Pre-Shared Key) mode of WPA (Wi-Fi Protected Access) [WPA] or IEEE
   802.11i [802.11i].  In this document, the key shared between a
   station and an AP is referred to as the PMK (Pair-wise Master Key).
   The PMK is derived from the EAP AAA-Key as a result of successful
   PANA authentication.  In this model, MAC addresses are used as the
   device identifiers in PANA.
"

Yoshihiro Ohba

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From: "Mohan Parthasarathy" <[email-masked]>
Date: Sun, 19 Dec 2004 21:44:43 -0800

Yoshi,

> AAA-Key in the following way.
Which way ? I am assuming that this question is the same one as i raised.
There were multiple APs and one PaC. How did each one of them derive
the key  from AAA-key ? Are you suggesting that we just say that it is derived
from AAA-key and leave the details out ?

-mohan

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From: Yoshihiro Ohba <[email-masked]>
Date: Mon, 20 Dec 2004 00:17:54 -0500

> from AAA-key and leave the details out ?

Yes.  This is what we are doing for pana-ipsec (pana-fwk draft does
not define key derivation algorithm for IKE PSK).  The exact key
derivation algorithm for IEEE 802.11i PMK can be defined in a separate
document (I don't know if such a document should be defined in IETF.)

Yoshihiro Ohba

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From: Julien Bournelle <[email-masked]>
Date: Tue, 21 Dec 2004 10:41:15 +0100

Hi all,

> document (I don't know if such a document should be defined in IETF.)

I may be worng but in pana-ipsec, we explain how to derive the IKE psk
at the PaC and EP.
"
   IKE pre-shared key is derived as follows.  
     
   IKE Pre-shared Key = HMAC-SHA-1 (AAA-key, "IKE-preshared key" |  
                           Session ID | Key-ID | EP-address)  
 "

So that PaC and EP knows which key will be used in IKE phase I.

I guess that we need the equivalent specification for 802.11i. So if we
don't specify it in the PANA FWK document, maybe we should write a
pana-802.11i WG I-D ?    

-- 
[email-masked]

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From: Rafa Marin Lopez <[email-masked]>
Date: Tue, 21 Dec 2004 11:41:02 +0100

Hi Julien ...

I agree with you it is an option though also as Yoshi say I don't know 
if it should be placed on in a IETF document.

what do others think?

Regards.

-- 
------------------------------------------------------
Rafael Marin Lopez
Faculty of Computer Science-University of Murcia
30071 Murcia - Spain
Telf: +34968367645    e-mail: [email-masked]
------------------------------------------------------

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From: "Mohan Parthasarathy" <[email-masked]>
Date: Tue, 21 Dec 2004 18:15:19 -0800

> if it should be placed on in a IETF document.
I am okay with the current position of leaving the details to a different document.
If there is sufficient interest, one can always write up another document describing
the details. Perhaps, we should state this clearly in the framework document.

-mohan