Re: [dmarc-ietf] Fwd: New Version Notification for draft-srose-dkim-ecc-00.txt

[Vladimir Dubrovin <[e-mail]>]

Hello Scott,

it may be good to cover compatibility issues, because otherwise there
are little chances to succeed the older but more compatible protocols in
nearest future.  The possible (but probably not the best one) solution is:

1. produce 2 different DKIM-Signatures with 2 different selectors:
slector1  with SHA-1 + RSA and selector2 one with  SHA-512 + ECDSA
2. add an additional field to either selector1 DKIM DNS record (need to
consult RFC if it's allowed) or to DKIM-Signature with selector1 (it's
allowed but probably is not enough to protect against downgrade) to
indicate the selector is legacy-only, e.g. o=sha512/eccp256 to indicate
this selector should be ignored if verifier supports sha-512 and eccp256.

Legacy verifier has valid DKIM-Signature with sha1+rsa
Compatible verifier ignores sha1+rsa and choose sha-512+ECDSA

I can imagine few more ways to resolve compatibility issues, but this
one seems to be a simplest.


06.04.2017 20:32, Scott Rose пишет:
> This may be of interest to this group, as there isn't an active DKIM
> WG anymore.  This is my first attempt to produce a draft about
> defining new digital algorithms for DKIM.  I'm trying to keep this
> short i.e. only define a few IANA registry entries and that's it.
>
> I'm trying to head off a potential issue for organizations that are
> told to migrate to ECDSA or looking for algorithm agility that doesn't
> involve using SHA-1.
>
> Comments welcome and needed. Including being told this isn't needed
> (though I think it might be).
>
> Scott Rose
>
> NIST
>
>
>
> -------- Forwarded Message --------
> Subject:     New Version Notification for draft-srose-dkim-ecc-00.txt
> Date:     Thu, 6 Apr 2017 10:26:43 -0700
> From:     [e-mail]
> To:     Scott Rose <[e-mail]>
>
>
>
> A new version of I-D, draft-srose-dkim-ecc-00.txt
> has been successfully submitted by Scott Rose and posted to the
> IETF repository.
>
> Name:        draft-srose-dkim-ecc
> Revision:    00
> Title:        Defining Elliptic Curve Cryptography Algorithms for use
> with DKIM
> Document date:    2017-04-06
> Group:        Individual Submission
> Pages:        6
> URL:           
> https://www.ietf.org/internet-drafts/draft-srose-dkim-ecc-00.txt
> Status:         https://datatracker.ietf.org/doc/draft-srose-dkim-ecc/
> Htmlized:       https://tools.ietf.org/html/draft-srose-dkim-ecc-00
> Htmlized:      
> https://datatracker.ietf.org/doc/html/draft-srose-dkim-ecc-00
>
>
> Abstract:
>    DomainKeys Identified Mail (DKIM) uses digital signature to associate
>    a message with a given sending domain.  Currently, there is only one
>    cryptography algorithm defined for use with DKIM (RSA).  This
>    document defines four new elliptic curve cryptography algorithms for
>    use with DKIM.  This will allow for algorithm agility if a weakness
>    is found in RSA, and allows for smaller key length to provide the
>    same digital signature strength.
>
>                                                                                  
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> The IETF Secretariat
>
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-- 
Vladimir Dubrovin
@Mail.Ru