Subject: [eap] EAP Key Management Framework

From: Rafa Marín López <[email-masked]>
Date: Wed, 14 Jan 2004 20:05:43 +0100

Hello all

I am reading EAP Key Management Framework draft... and I am a bit 
confused ...

Figure 4 shows that MSK is placed on Authenticator but only AAA-key is 
transported from AAA server... ¿? ... furthermore the text tells MSK is 
transported to Authenticator... in another places AAA-key is carried ... 
I think it would be better to say : AAA - key is carried to 
authenticator and it could be the MSK (as appendix E tells)... what do 
you think?

Regard.

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

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

---

From: Rafa Marín López <[email-masked]>
Date: Mon, 19 Jan 2004 19:04:32 +0100

Rafa Marín López wrote:

> transported from AAA server... ¿? ... furthermore the text tells MSK 
> is transported to Authenticator... in another places AAA-key is 
> carried ... I think it would be better to say : AAA - key is carried 
> to authenticator and it could be the MSK (as appendix E tells)... what 
> do you think?
>
> Regard.
>

---

From: Jari Arkko <[email-masked]>
Date: Wed, 21 Jan 2004 08:41:05 +0200

Rafa Marín Lopez wrote:

>> transported from AAA server... ? ... furthermore the text tells MSK 

I'm not sure I can find the place that you find confusing. Can you
point us to the location in the text where it says that the MSK is
transported to the authenticator?

Or perhaps its this text:

    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.

This may be confusing, as the subject of transportation is not perhaps
clear. How about this instead:

    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.

--Jari

---

From: Rafa Marín López <[email-masked]>
Date: Wed, 21 Jan 2004 15:35:38 +0100

Rafa Marín López wrote:

> Hello Jari
>
> Iniatilly in Figure 4 , authenticator box has a MSK written  on it. So 
> I could understand which MSK is transported.... about text... page 30
>
> 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
>
>
>
>
> So I think it would be better to say something like : AAA - key is 
> carried to authenticator and it could be the MSK (as appendix E tells)
>
> Regards...
>
>
>
> Jari Arkko wrote:
>
>> Rafa Marín Lopez wrote:
>>
>>>> Figure 4 shows that MSK is placed on Authenticator but only AAA-key 
>>>> is transported from AAA server... ? ... furthermore the text tells 
>>>> MSK is transported to Authenticator... in another places AAA-key is 
>>>> carried ... I think it would be better to say : AAA - key is 
>>>> carried to authenticator and it could be the MSK (as appendix E 
>>>> tells)... what do you think?
>>>
>>>
>>

---

From: Jari Arkko <[email-masked]>
Date: Thu, 22 Jan 2004 08:53:29 +0200

Rafa Marín López wrote:
> Hello Jari
> 
> Iniatilly in Figure 4 , authenticator box has a MSK written  on it. So I 

Ah, now I see it. Figure 4 is IMHO wrong. MSK in the authenticator should
be the AAA-Key; as you see the arrow transports the AAA-Key and not the MSK.

> could understand which MSK is transported.... about text... page 30
> 
> ---> The MSK is distributed by the backend authentication server to the 
> authenticator

This is wrong too, I think. s/MSK/AAA-Key/g in this paragraph.

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

      with

--Jari