AW: [Emu] EAP-GPSK: Ciphersuites

Hi Lakshminath, 

I am not sure that the group wants to use CCM. 
(If you are referring to this part of your mail.)

Ciao
Hannes

> -----Ursprüngliche Nachricht-----
> Von: Lakshminath Dondeti [mailto:ldondeti@qualcomm.com] 
> Gesendet: Dienstag, 22. August 2006 11:44
> An: Hannes Tschofenig
> Cc: emu@ietf.org
> Betreff: Re: [Emu] EAP-GPSK: Ciphersuites
> 
> I guess we agree to disagree.  The addition integrity checksum is 
> spurious in my view and I believe we can define things so that 
> combined modes can be employed without encrypting anything, so I am 
> somewhat confused here.  What's your opinion on the latter 
> part of my email?
> 
> thanks,
> Lakshminath
> 
> At 05:12 PM 8/22/2006, Hannes Tschofenig wrote:
> >Hi Lakshminath,
> >
> >Lakshminath  Dondeti schrieb:
> >>At the expense of generating some confusion, here is my 
> take on this:
> >>The objection is to having to carry multiple integrity checksums in 
> >>GPSK, if we used the combined mode *and* an integrity algorithm.
> >
> >I don't agree with you. There is no reason to optimize a few bits in 
> >a pre-shared secret method.
> >Note that we are not talking about a protocol for data transfer.
> >We wanted the flexibility to use different cipher suites. We do not 
> >only want to use cipher suites that provide authenticated encryption 
> >(since we almost have nothing to encrypt; currently 1 bit and almost 
> >no EAP method provides this functionality).
> >
> >Ciao
> >Hannes
> >
> >>I think CCM is fine for instance, the only catch is that we need to 
> >>make sure and define AAD for CCM carefully to include appropriate 
> >>data into the integrity checksum calculation.  So, once we define 
> >>CCM as the mode, we shouldn't need AES-CMAC-128 if 
> encryption is being used.
> >>I would suggest using CCM and specifying the use of it fully so it 
> >>can be used without misunderstandings.  If you want me to put some 
> >>time into writing that up, let me know.
> >>cheers,
> >>Lakshminath
> >>At 10:55 PM 8/20/2006, Hannes Tschofenig wrote:
> >>>Hi all,
> >>>
> >>>the current version of the document
> >>>http://tools.ietf.org/wg/emu/draft-clancy-emu-eap-shared-se
cret-01.txt
> >>>still supports AES-EAX:
> >>>
> >>>    
> +-----------+----+-------------+---------------+--------------------+
> >>>    | CSuite/   | KS | Encryption  | Integrity     | Key 
> Derivation     |
> >>>    | Specifier |    |             |               | 
> Function           |
> >>>    
> +-----------+----+-------------+---------------+--------------------+
> >>>    | 0x000001  | 16 | AES-EAX-128 | AES-CMAC-128  | 
> GKDF-128           |
> >>>    
> +-----------+----+-------------+---------------+--------------------+
> >>>
> >>>At the IETF#66 EMU meeting AES CCM was suggested.
> >>>
> >>>Later, it got the impression that AES-CBC was more appreciated. 
> >>>Should we update the draft with AES-CBC?
> >>>
> >>>Ciao
> >>>Hannes
> >>>
> >>>
> >>>_______________________________________________
> >>>Emu mailing list
> >>>Emu@ietf.org
> >>>https://www1.ietf.org/mailman/listinfo/emu
> 
> 
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