Re: [Dcrup] I-D draft-ietf-dcrup-dkim-crypto-06

[Scott Kitterman <[e-mail]>]

On Monday, September 18, 2017 10:13:52 AM Jim Fenton wrote:
> On 9/15/17 10:15 PM, John Levine wrote:
> > In article <1739837.QWERb01LVO@kitterma-e6430> you write:
> >>> As far as I can tell, this is about as done as it's going to get.
> >> 
> >> Do we really need to add both rsafp and ed25519?
> >> 
> >> I thought we had ~agreed (or at least discussed) earlier to only add
> >> ed25519> 
> > In July I proposed only doing EC but there was no consensus.  I would
> > prefer not to rerun old arguments unless we have learned something new in
> > the meantime.
> I haven't found your proposal, but I asked on Jabber at the Prague
> meeting whether one or the other would suffice, and repeated that
> question on the list. See thread "Do we need both hashed RSA and
> elliptic curves?" that begins on 21 July. There were responses from 7
> people including you, and I didn't see anyone arguing that we should
> have both (although it's not my place to judge consensus).
> 
> We would be doing a disservice if we require everyone to support two
> ways of solving the key length problem unless there is a compelling
> reason to do so.
> 
> I also support the use of elliptic curve signatures rather than rsafp.
> Part of the reason is that rsafp may have IPR issues (see disclosure
> 3025). AFAIK EC signatures avoid this problem unless the selector DNS
> record contains a hash of the public key, which shouldn't be necessary
> because the key is shorter. I have no opinion on the choice of curve used.

Those all make sense to me.

I don't recall anyone pushing hard for retaining both and, while I agree there 
was never a formal consensus call by the chairs, it seemed like that was 
definitely the direction the group was leaning.

Scott K