Re: [IPsec] Working Group Last Call: draft-ietf-ipsecme-esp-ah-reqts

["Valery Smyslov" <[e-mail]>]

Hi Paul,

> > The draft lists the following trasforms based on AES cipher:
> >
> > AES-GCM
> > AES-CCM
> > AES-CTR
> > AES-128-CBC
> > AES-GMAC
> > AES-XCBC-MAC-96
> >
> > All these transforms, except for AES-XCBC-MAC-96,
> > allows to be used with different key lengths - 128, 192 and 256 bits.
> > It looks strange to me that, unlike the others, AES-128-CBC
> > has key length explicitely specified in the draft. Why it differs in
> > this respect from the others? What about AES-192-CBC and
> > AES-256-CBC - are they also "MUST" or "MAY"? Or even "MUST NOT"? :-)
> >
> > I think the draft should either:
> > - remove explicit key length from AES-128-CBC and make it just AES-CBC
> > - add explicit key length to all other AES-based transforms (except for 
> > AES-XCBC-MAC-96)
> > - leave things as is, but explain why AES-CBC differs in this respect 
> > from the others
>
> The next draft changes AES-128-CBC to AES-CBC, and says:
>
> In the following sections, all AES modes are for 128-bit AES. 192-bit AES
> MAY be supported for those modes, but the requirements here are for 
> 128-bit AES.

And please, add the same words for 256-bit AES as for 192-bits AES.

Regards,
Valery.

> --Paul Hoffman