Subject: [eap] Proposed Resolution to Issue 216: MSK Issues

From: Bernard Aboba <[email-masked]>
Date: Wed, 3 Mar 2004 20:01:55 -0800 (PST)

The text of Issue 216 is enclosed below.  The proposed resolution is to
accept the proposed changes.  Any objections?

-----------------------------------------------------------------------
Issue 216: MSK issues
Submitter name: Jari Arkko
Submitter email address: [email-masked]
Date first submitted: 1/21/2004
Reference:
http://mail.frascone.com/pipermail/public/eap/2004-January/002172.html
Document: Keying Framework-01
Comment type: 'T'echnical
Priority: 'S'
Section: Section 2.3, 4.1
Rationale/Explanation of issue:

Here's a summary of the modifications I would do to fix this:

   o  In Figure 4, s/MSK/AAA-Key/ in the Authenticator box.

   o  In Section 4.1, replace the paragraph

    Utilizing the AAA protocol, the authenticator and backend
    authentication server mutually authenticate and derive session keys
    known only to them, used to provide per-packet integrity and replay
    protection, authentication and confidentiality.  The MSK is
    distributed by the backend authentication server to the authenticator
    over this channel, bound to attributes constraining its usage, as
    part of the AAA-Token.  The binding of attributes to the MSK within a
    protected package is important so the authenticator receiving the
    AAA-Token can determine that it has not been compromised, and that
    the keying material has not been replayed, or mis-directed in some
    way.

      with

    Utilizing the AAA protocol, the authenticator and backend
    authentication server mutually authenticate and derive session keys
    known only to them, used to provide per-packet integrity and replay
    protection, authentication and confidentiality.  The AAA-Key is
    distributed by the backend authentication server to the authenticator
    over this channel, bound to attributes constraining its usage, as
    part of the AAA-Token.  The binding of attributes to the AAA-Key
within a
    protected package is important so the authenticator receiving the
    AAA-Token can determine that it has not been compromised, and that
    the keying material has not been replayed, or mis-directed in some
    way.

   o  Section 2.3, replace the paragraph

    The MSK and EMSK are used to derive the AAA-Key and key name which
    are enclosed within the AAA-Token, transported to the  NAS by the AAA
    server, and used within the secure association protocol for
    derivation of Transient Session Keys (TSKs) required for the
    negotiated ciphersuite.

      with

    The MSK and EMSK are used to derive the AAA-Key and key name. AAA-Key
    and key name are enclosed within the AAA-Token, which is transported
to the
    NAS by the AAA server, and used within the secure association protocol
for
    derivation of Transient Session Keys (TSKs) required for the
    negotiated ciphersuite.

_______________________________________________
eap mailing list
[email-masked]
http://mail.frascone.com/mailman/listinfo/eap

---

From: "Joseph Salowey" <[email-masked]>
Date: Wed, 3 Mar 2004 20:30:17 -0800

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] 
> On Behalf Of Bernard Aboba
> Sent: Wednesday, March 03, 2004 8:02 PM
> To: [email-masked]
> Subject: [eap] Proposed Resolution to Issue 216: MSK Issues
> 
> 
> The text of Issue 216 is enclosed below.  The proposed 
> resolution is to accept the proposed changes.  Any objections?
> 
>     part of the AAA-Token.  The binding of attributes to the 
> AAA-Key within a

[Joe] I prefer the original text. We should use the MSK instead of
AAA-Key.

>     and key name are enclosed within the AAA-Token, which is 
> transported to the
>     NAS by the AAA server, and used within the secure 
> association protocol for

[Joe] The MSK instead of AAA-Key.  It is not clear that it is a good
idea to derive the name from a key.  I think it is preferable that the
name be exported from the method.