Free and open source software and your patents

by Rowan Wilson on 16 April 2008 , last updated


The question of how free and open source software licensing interacts with the ownership of software patents often arises among professionals charged with maximising value and return from software property. This document explains some of the most common issues that surround this topic.

What are the issues?

If you do not own any software patents, and do not plan to, there are obviously no issues specific to interactions between your patents and licensing. Where a person or institution does own software patents or does intend to, however, the implications of free and open source licensing must be considered carefully before adopting such a licensing strategy. Licensing your code in this way may grant rights under patent law to the recipients of your code, and as the free and open source licensing model is designed to disseminate software and its associated licence as widely as possible, such a patent grant will also be, potentially, very wide both in the rights it grants and the audience to which it grants them.

In addition, software patents themselves are controversial. Many software authors and technology companies in both the open and closed source spheres argue that software inventions are too abstract to legitimately enjoy patent protection, being more akin to mathematical algorithms than concrete industrial devices. In Europe, software is nominally excluded from patentability by section 52 of the European Patent Convention 1973. However, subsequent granting practice by both the European Patent Office and national patent examination bodies has made this exclusion somewhat moot. In the US, software is not excluded from patentability, although many argue that it should be, and recent decisions by the US Supreme Court have brought the idea into question without providing any generally applicable rulings.

Specifically in the free and open source software community there is almost universal opposition to the notion of the patentability of software. Free and open source development stresses the ability of individuals to write and release code freely. The existence of software patents is seen by this community as seriously prejudicing that ability, arguably necessitating expensive patent searches before code can be safely released. The success of a free or open source software project will largely depend upon the willingness of the user and developer community to engage with the software developed by the project, so it is worth bearing in mind the attitude of the community-at-large to software patents.

What do the licences do?

Free and open source licences primarily grant rights to modify and redistribute the software that they cover. When the software is distributed by someone other than the licensor, the recipients will either gain an identical sub-licence from the distributor or a licence direct from the original licensor, depending on the terms of the licence. Many free and open source software licences explicitly grant rights in perpetuity. Even where they do not, the fact that all recipients are entitled to redistribute freely makes the goal of effectively terminating the licence close to unachievable. For this reason it is best to think of any software licensed in this way as perpetually licensed.

All free and open source software licences permit free adaptation of the material they cover and distribution of these adapted versions. Some licences, such as the GNU General Public License (all versions), mandate that the adaptations of software that it covers must be distributed under the same licence, if they are to be distributed at all. This principle is often referred to as ‘copyleft’, and exists in many free and open source licences. ‘Copyleft’ licences vary in the extent to which they mandate that adaptations be distributed wholly under the terms of the licence in question; the GNU General Public License (all versions) specifies that any work containing GPL-licensed code must be distributed under the terms of the GPL, while the Mozilla Public License allows separate, newly added sections of the adapted program to bear any licence, while the remainder must be under the MPL. This ‘gradient’ of copyleft between different licences is often characterised as running from ‘strong’ to ‘weak’.

Other ‘permissive’ licences, such as the MIT License, permit the software they cover to be adapted and the result distributed in a wide variety of ways, stipulating only that where the code is unadapted the author must be credited, and where it is adapted the author’s permission is required before their name can be attached to the adaptation.

Some free and open source software licences also explicitly grant the patent rights necessary for the purposes of using, adapting and distributing the code, for example the Apache License v2, the GNU General Public License v3 and the Eclipse Public License. In some jurisdictions, including the UK, it is highly probable that even those free and open source software licences that do not explicitly grant patent rights do in fact provide them implicitly. After all, giving permission to perform a specific act strongly implies permission to perform the steps needed to do so. Thus the permission to redistribute the software granted by all free and open source licences - it can be argued - implies the granting of the right to make use of any of the licensor’s patents which would be infringed by the distribution of the code.

What does this mean for me and my patents?

In general, free and open source software licensing is inconsistent with charging for the licensing of patents embodied in that software. As explained above, the wide and effectively perpetual grant that is made by free and open source software licences provides a low-cost route to use and distribution for potential licensees. As a result potential licensees are unlikely to want to pay for a licence.

Having said that, there are approaches to development and licensing which do allow for charging for embodied patents. It is possible, of course, to design software in a modular fashion that will allow a section of code embodying a patent to be kept separate from the remainder of the code in a software project, and to license these two sections separately. Provided that the code which does not embody the patent is useful in itself it may find a user and developer community who are happy to receive it. Please get in touch if you are interested in discussing this.

The question of the effect of adaptation is often raised when discussing free and open source software and patents. At OSS Watch we have often been asked whether a piece of free or open source code cannot be used as a kind of skeleton key to the software patents held by an individual or institution. Essentially this boils down to two issues:

  • Can free or open source software that I release be legitimately adapted to embody a patent of mine that I do not wish to license in this way?
  • Can free or open source software that I release be used to gain licences to patents which did not exist at the time I released the software?

The answer to both these questions is ‘no’. In the first case, subsequent adaptations of the software are not covered by your explicit or implied patent grant covering the original software. Anyone who added code embodying another of your patents would be infringing that patent in the usual way. In the second case it can be difficult to establish precisely when a free or open source software licence has been initiated in a particular case. However the issue of access to subsequently obtained patents does not arise – chiefly because by releasing the software with its source code in the first place you will have fatally prejudiced your chances of obtaining a patent on processes embodied in the code later on. Thus while the second concern is not a valid one, it does highlight the necessity of careful and thoughtful consideration of free or open source software release before it is undertaken. Release of source code is equivalent to publication, and will close off opportunities to obtain patents on processes embodied in the code.

A more detailed explanation and the legal background in Europe and the USA can be found in our software patents briefing note.

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