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

[ianG <[e-mail]>]

On 5/05/2014 19:14 pm, Nico Williams wrote:
> 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.


Right.  I suppose it could be read either way, and I read it the other way.


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


Hmmm, anyone have the refs?


> 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.


I was briskly told to make the case, get to the back of the queue ;)



iang