For years, Microsoft has spurned the existing open standards (RFC2015 and RFC3156) which provide for "sender verification" through cryptographically signed messages. But growing concern over spam and viral plagues has reached the point that Microsoft felt it had to do something to combat them. That something is their Caller ID plan. That plan includes a license that states:
Microsoft believes that it has patent rights (patent(s) and/or pending applications(s)) (sic) that are necessary for you to license in order to make, sell, or distribute software programs that comply with one or more aspects of the Caller ID for E-mail Specification.
Microsoft and its Affiliates hereby grant you ("Licensee") a fully paid, royalty-free, non-exclusive, worldwide license under Microsoft's Necessary Claims to make, use, sell, offer to sell, import, and otherwise distribute Licensed Implementations, provided, Licensee, on behalf of itself and its Affiliates, hereby grants Microsoft and all other Specification Licensees, a reciprocal fully paid, royalty-free, non-exclusive, worldwide, nontransferable, non-sublicenseable, license under Necessary Claims of Licensee to make, use, sell, offer to sell, import, and otherwise distribute Licensed implementations.
Asked to comment by email this morning on whether or not that portion of the license would prohibit its use in GPL-licensed software, Eben Moglen said:
This license does not prohibit the use of licensed claims--if there are any--in GPL'd software.
That Microsoft asserts unspecified patent claims over something it is trying to make a de facto standard, however, should give pause. There is no reason whatever for adoption of a patent-encumbered protocol in this area. If Microsoft does indeed possess essential claims it should disclose what those claims are, so that the implementer community can
decide how to define a standard that no one owns, even partially. If Microsoft refuses to disclose what essential claims it has, Caller-ID for E-Mail should be rejected in favor of SPF or another alternative.
Professor Moglen contacted NewsForge later today and said that -- based on other text he was being shown from the license -- it may prohibit GPL'd implementation. My deepest apologies to our readers and to Professor Moglen for not including the following portions of the license in my initial query this morning:
If you distribute, license or sell a Licensed Implementation, this license is conditioned upon you requiring that the following notice be prominently displayed in all copies and derivative works of your source code and in copies of the documentation and licenses associated with your Licensed Implementation:
"This product may incorporate intellectual property owned by Microsoft Corporation. If you would like a license from Microsoft, you need to contact Microsoft directly."
By including the above notice in a Licensed Implementation, you will be deemed to have accepted the terms and conditions of this license. You are not licensed to distribute a Licensed Implementation under license terms and conditions that prohibit the terms and conditions of this license.
Professor Moglen added these comments about the additional wording:
It's not the advertising clause, but the "deemed accepted."
Under section 7 of the GPL, "conditions imposed" on the putative
licensor that prevent him from passing to all others the freedoms
conveyed by GPL preclude his distribution under GPL. If the license
offered by Microsoft didn't require acceptance, then there would be no
"conditions imposed" on a developer who didn't *actually* accept the
license. But Microsoft here says that if you distribute you are
deemed to have accepted (they are using the GPL's own approach against
it). Whether that works the same way in patent terms that it works in
copyright terms is not entirely certain, but the question is too close
to permit doubtful developers to proceed. I would not hold that this
license, containing both additional restrictions and an implicit or
constructive acceptance clause is consistent with GPL section 7, hence
the license effectively ousts GPL'd implementation.
Note, however, that a developer could specifically *disclaim* the
Microsoft patent license, which--since it does not actually identify
any patent claims being licensed--could be said to be a nullity in any
event. Such a developer could legitimately distribute under GPL,
which would arguably be the wiser course.