Re: [saag] A case against algorithm agility (long)

[Nico Williams <[e-mail]>]

On Mon, May 5, 2014 at 12:26 PM, ianG <[e-mail]> wrote:
> Meet the draft:
>
> https://datatracker.ietf.org/doc/draft-iab-crypto-alg-agility/?include_text=1
>
> Especially 2.1:
>
>    Some approaches carry one identifier for each algorithm that is used.
>    Other approaches carry one identifier for a suite of algorithms.
>    Either approach is acceptable; however, designers are encouraged to
>    pick one of these approaches and use it consistently throughout the
>    protocol.

The I-D is a bit barebones at this time -- that tends to be the case
with -00s...  It certainly needs to expand on the details of algorithm
negotiation quite a bit.  In particular it should say that one should
not design protocols to negotiate ciphers and cipher modes separately.
 Text on the pros/cons of a-la-carte vs. cartesian product negotiation
would be handy.

ISTR presentations to SAAG about algorithm agility that could be
leveraged here.  IIRC it was EKR who presented.

Nico


PS: There was no need to post that long screed.  It would have been
better to focus on the cipher-and-mode matter first, especially if you
don't object to a-la-carte negotiation in general.  Long rambling
rants can be a bit of a DoS on the community.  Try to keep it shorter.
 Edit, edit, edit until you have a concise post.