HostAP Digest, Vol 100, Issue 26

Jouni Malinen j
Wed Aug 17 07:18:55 PDT 2011

On Wed, Aug 17, 2011 at 07:36:53PM +0530, uday kiran wrote:
> >
> > > Where did you read that? AES is defined for multiple key lengths, but
> > CCMP is only defined for the case where a 128-bit key is used.
> >
> > Sorry Jouni , I got confused with AES key lengths.
> Is RFC 3610 the one that talks about CCMP ?

Strictly speaking, it defines the CCM mode that is used in CCMP, but it
does not define CCMP.

> In the given RFC, there is mention in the introduction section that CCMP can
> be extended to other block sizes.

There is a comment that CCM could be extended to other block sizes. This
does not mean that this would have been done or that it would apply to
CCMP (and this is talking about block size, not key length).

> If I want to implement 192,256 key lenght support , then does it require
> support from hardware ? I am asking this question because i am assuming that
> key length is not dependent on hardware .Please clarify .

That would require defining a new cipher suite since CCMP is not defined
to do that. In addition, you would need to implement this new cipher
suite either in software or hardware.

Jouni Malinen                                            PGP id EFC895FA

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