[ietf-dkim] Fluffy DKIM questions

[Eric Allman]

I can answer some of these, but not all.

--On May 15, 2007 12:08:09 PM -0700 Steve Atkins <steve at blighty.com> 
wrote:
> 1. Does anyone have an overview of the benefits and
>      drawbacks to DK and DKIM in general?

I think there's been several short descriptions, although I don't 
think I've seen a definitive analysis.  I believe the intro to the DK 
document includes a summary, but I haven't actually read it in a year 
or so.

> 2. How about the differences between DK and DKIM?

I've got that on my to-do list, but I'm not going to be able to get 
to it before next week.

> 3. Is a valid DK signature a valid DKIM signature?

No.

> 3b. If the general answer to that is "no", are some subsets
>      of DK signatures also valid DKIM signatures?

No.  Among other things, they use different signature headers.

> 4. What are the Intellectual Property implications of
>      deploying DKIM? (The Yahoo DK license agreement
>      has scared off a number of people from implementing
>      or using it).

So far as I know, everything should be completely open for use.  I 
think that the Yahoo! claims may apply to DKIM as well, but so far as 
I know they have completely addressed those issues.  Their most 
recent IPR disclosure is at 
<https://datatracker.ietf.org/public/ipr_detail_show.cgi?ipr_id=716>. 
The interesting bit reads:

        Yahoo! licenses its Necessary Patent Claims contained in the
        patent(s) and patent application(s) disclosed above under
        either of two separate license agreements, one of which is
        the DomainKeys Patent License Agreement (v1.2), and the other
        is the GNU General Public License v2.0 (and no other version).

I'm not sure what it means to apply the GPL to a patent license, but 
there it is.

eric