Subject: [Dcrup] I-D Action: draft-ietf-dcrup-dkim-ecc-00.txt

From: [email-masked]
Date: Fri, 02 Jun 2017 07:41:36 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the DKIM Crypto Update of the IETF.

        Title           : Defining Elliptic Curve Cryptography Algorithms for use with DKIM
        Author          : Scott Rose
	Filename        : draft-ietf-dcrup-dkim-ecc-00.txt
	Pages           : 7
	Date            : 2017-06-02

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.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-ecc/

There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-dcrup-dkim-ecc-00
https://datatracker.ietf.org/doc/html/draft-ietf-dcrup-dkim-ecc-00

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.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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From: "Rose, Scott" <[email-masked]>
Date: Fri, 2 Jun 2017 10:46:59 -0400

Updated to reflect WG status.  Also made the following changes:

1. Reduced new algorithms list to just one (ECDSA P=256).

2. Included revised definition of key:value pairs for DKIM keys and 
signatures.  One thing I thought about: should the “k=“ in keys to 
be mandatory now that RSA isn’t the only algorithm?  Or leave the 
default as is, so that anyone using ECDSA must use the “k=“ tag to 
signal its use?

3. Just noticed that the format is mess up for the ABNF notation - dang. 
  Will fix that.

Scott

On 2 Jun 2017, at 10:41, [email-masked] wrote:

> _______________________________________________
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> https://www.ietf.org/mailman/listinfo/dcrup

===================================
Scott Rose
NIST ITL
[email-masked]
+1-301-975-8439
GV: +1-571-249-3671
===================================

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From: Russ Housley <[email-masked]>
Date: Fri, 2 Jun 2017 10:53:29 -0400

Scott:

Since ECDSA P-256 and SHA-256 have the same security strength, what is the reason for adding SHA-512 at this time?  I do not see anything in the Introduction or Security Considerations to answer that question.

Russ

> On Jun 2, 2017, at 10:46 AM, Rose, Scott <[email-masked]> wrote:
> 
> 2. Included revised definition of key:value pairs for DKIM keys and signatures.  One thing I thought about: should the “k=“ in keys to be mandatory now that RSA isn’t the only algorithm?  Or leave the default as is, so that anyone using ECDSA must use the “k=“ tag to signal its use?
> 
> 3. Just noticed that the format is mess up for the ABNF notation - dang.  Will fix that.
> 
> Scott
>

---

From: "Rose, Scott" <[email-masked]>
Date: Fri, 2 Jun 2017 11:06:32 -0400

Mainly to have something pre-defined if SHA-256 is found to be 
vulnerable.  I’m not very concerned about that, if the community is 
responsive in the event that does happen.  I have no qualms about 
dropping it since it gives the draft a single focus.  It’s more for 
potential future-proofing.

Scott

On 2 Jun 2017, at 10:53, Russ Housley wrote:

> Scott:
>
> Since ECDSA P-256 and SHA-256 have the same security strength, what is 
> the reason for adding SHA-512 at this time?  I do not see anything in 
> the Introduction or Security Considerations to answer that question.
>
> Russ
>
>
>
>> signatures.  One thing I thought about: should the “k=“ in keys 
>> to be mandatory now that RSA isn’t the only algorithm?  Or leave 
>> the default as is, so that anyone using ECDSA must use the “k=“ 
>> tag to signal its use?
>>

---

From: "John Levine" <[email-masked]>
Date: 3 Jun 2017 11:12:50 -0000

>default as is, so that anyone using ECDSA must use the “k=“ tag to 

It needs to be backward compatible, so no k= still means RSA.

R's,
John