Re: [Dcrup] new version draft-ietf-dcrup-dkim-crypto-04

[Martin Thomson <[e-mail]>]

On 7 August 2017 at 12:53, John R Levine <[e-mail]> wrote:
> So we have to update 6376 to add all the new signature
> methods that a signer might use.  Also remember that the current unhashed
> RSA works just fine for the large fraction of signers whose DNS provisioning
> system isn't broken, so we're not deprecating it.

That wasn't my point.  And it might just come back to us disagreeing
what "updates" means, but 6376 clearly establishes an extension point
for new signature algorithms.  Part of that includes the assumption
that verifiers have to be willing to verify any defined algorithm (and
the converse, that signers risk messages being marked as bad because
they fail to include signatures over old algorithms when they add new
ones).

I don't believe that adding a signature algorithm means that you need
to update 6376.

> I took out the second and now says signatures MUST be at
> least 1024 bits and SHOULD be 2048 bits, and verifiers MUST NOT accept
> shorter than 1024.

That works for me.