This article appeared years ago in the OuterCurve blog, but the link to it is broken, now, so on request I have reproduced it — or at least an early draft of it — here. This was a companion piece to a conference at Santa Clara law school, but that link is broken, too! I am happy anyone cares to read one of my articles after so many years. I hope someone can use this information to go squish some patent trolls.
When Richard Stallman wrote in GPL2 “any free program is threatened constantly by software patents” he crystallized the ideological battle between open source software and the software patent business. In 1991 when GPL2 was released, that battle was in its nascent stages. Today each of open source licensing and software patenting has come to its fullest flower, though their growth generally proceeds on orthogonal axes; most open source software is never accused of patent infringement and most software patent infringement suits don’t accuse open source software. In fact, they so seldom interact directly that the lawyers who practice in these areas do not overlap much. This means those defending patent infringement suits may not be thinking about the tactics open source patent licensing offers to patent defendants.
In patent litigation defense, every little bit helps. Today, patent defendants should be paying attention to open source licensing and its possible effect on patent infringement claims. When you are sued for patent infringement, by anyone other than a pure non-practicing entity (aka patent troll), one of your first lines of internal investigation should be the open source position of the plaintiff, and, if you are considering retaliatory patent claims, your own open source position as well.
When Open Source and Patents Mix
Patent lawyers may be surprised to know that while today, most companies today use open source software, most of them struggle greatly with implementing the internal controls to coordinate their use of open source software with their patent portfolio management. This means it is quite possible that a company is seeking patent protection, or seeking to enforce patents, that read on open source software the company is using or developing — a combination of activities that would often not be considered economically rational.
There have been at least two cases where defendants have successfully used open source license enforcement as a defensive tactic in a patent lawsuit. The first case is the one most often cited to support the enforceability of open source licenses; most people forget that the case started as a patent claim. In Jacobsen v. Katzer, both parties developed and distributed software for controlling model railroads — Jacobsen making his JMRI software available under an open source license free of charge, and Katzer (via his company Kamind Associates) selling commercial products under proprietary licenses. Jacobsen received a letter inviting him to license patents owned by Kamind, suggesting the patents were infringed by the JMRI software. Jacobsen filed a declaratory judgment action asking the court to rule that the patent was invalid due to prior art (or failure to disclose prior art including that of Jacobsen himself) or not infringed. As the patent case progressed, however, Jacobsen discovered that Katzer had copied some of Jacobsen’s open source software and used it in Katzer’s proprietary product, without the proper attributions and license notices. Jacobsen v. Katzer was finally settled in 2010, but only after becoming the seminal US case on open source licensing — not patent infringement — and resulting in a settlement payment by Katzer for violation of the open source license.
In Twin Peaks Software Inc. v. Red Hat, Inc., Twin Peaks Software (TPS), which made proprietary network backup software, sued Red Hat and Red Hat’s recently-acquired subsidiary Gluster. TPS claimed that the GlusterFS software — a network file system that aggregated multiple storage shares into a single volume — violated TPS’s patent covering TPS’s “Mirror File System” (MFS). Red Hat initially responded to the patent infringement suit denying the infringement and asserting that the patent was invalid, but later brought a counterclaim alleging the TPS products incorporated open source software from Red Hat’s product, without complying with GPL. Red Hat sought an injunction against the TPS products . The case ended soon in a settlement, suggesting that TPS thought better of pursuing its patent claims in light of the facts.
In both these cases, the patent plaintiff was using open source software of the defendant, and the patent defendant discovered a violation of the applicable open source license that it used to turn the tables on the plaintiff. In this way, open source license enforcement can be a substitute for a more traditional retaliatory patent claim. In each case, the plaintiff and defendant were in similar product markets — a very common context for patent litigation — which made the use of the defendant’s open source code by the plaintiff likely. The moral of this story, for a patent plaintiff, is that one should have a robust open source compliance program in place before asserting a patent in a related space.
There are other more subtle tactics as well. Open source licenses — particularly those written in the last 20 years — contain two kinds of provisions that bear upon patent litigation strategy. The first, and more straightforward, is the patent license. See for instance the license in Apache 2.0, which says:
3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted.
This license only applies to contributors, so a mere re-user or re-distributor of the software does not grant any rights. However, if a company has contributed to the software, under an open source license or under a similar contribution license, that company may have granted a license that can be used a defense to an infringement claim.
For example, suppose company P (patent plaintiff) sues company D (defendant) for patent infringement. However, Company P has contributed software embodying the claims of the asserted patent to a project covered by this license The Apache 2.0 license is a permissive license, so it may be easy for D to claim it is using software under this license. Raising this as a license defense can avoid liability — or at least, create an unexpected defense that will add significant cost to prosecuting the suit.
Now consider the defensive termination provision of Apache 2.0:
If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
This means that by filing the lawsuit, P may have given up any patent licenses it has received from any contributors to the software — which may include D or third parties who may be aligned with D. This provision applies to all licensees, not just contributors. Even if D is not a contributor with patent claims to bring, bringing the claim exposes P to potential liability. Pointing this out may shift the balance in favor of the defense.
It’s important to understand that patent defensive termination provisions in different open source licenses have different terms. Some, like Apache 2.0, are triggered by defensive claims, but some are not. Some, like MPL, (or the corresponding “liberty or death” provision in GPL3) also trigger a termination of the copyright license, making them an even more powerful defense tool.
Open Source Due Diligence — In Patent Litigation
So, the next time you are sued for patent infringement, you have not done your homework until you know:
- Is the plaintiff using any open source software of yours (related to the patent or not) in violation of the license?
- Does the asserted claim read on any open source software you are using? If so, would the complaint trigger a defensive termination provision that might apply to the plaintiff?
- Did the plaintiff contribute to any open source project any code under terms that would include a patent license? If so, do you have a defense under that license?
Investigating the last question can be an informational challenge, but it may not be as difficult as you think. Records regarding contributions may be available publicly, or open source projects may be willing to cooperate if it helps them defeat patent claims accusing their code.
The drafters of open source licenses intended to use the terms of those licenses to win a war against software patents, and whether they can do that remains to be seen, but in the meantime, don’t pass up the opportunity to use the principles of open source licensing to win your battles as well.