The Copyfree Standard Definition
The Copyfree Standard is a "layman's terms" specification of the characteristics that define a copyfree license -- essentially an itemized checklist implementing the copyfree policy. Before a license can be considered a copyfree license, it must conform to the requirements of the Copyfree Standard Definition as listed below. It should not be understood as a legal document, or as employing terms in a legally rigorous fashion; it is intended to describe the conditions of copyfree licensing in plain English, which may conflict at times with the precise meaning of terms established by legislation and court precedent.
The criteria for qualification as a copyfree license are:
A copyfree license does not place any restrictions on the use of the licensed material, and protects recipients of the material from such restrictions except insofar as explicit individual contractual agreements are concerned.
A copyfree license does not place any restrictions on the distribution of the licensed material except regarding the license itself, and protects recipients of the material from such restrictions except insofar as explicit individual contractual agreements are concerned.
Free Modification and Derivation
A copyfree license does not place any restrictions on the modification of -- and derivation from -- the licensed material external to the license itself, and protects recipients of the material from such restrictions except insofar as explicit individual contractual agreements may be concerned.
A copyfree license does not place any restrictions on materials outside of the licensed material itself, nor does it explicity limit the licensed materials in combination with materials external to the licensed material.
A copyfree license does not place any restrictions on who benefits from the terms of the licensed material, except in the event it specifies provisions to revoke its terms for those found to have violated the copyfree protections of the license. The license is also applicable to recipients of the material distributed under its terms without requiring the execution of any additional license by the distributing and receiving parties.
Copyfree Standard Compliance
The following is a set of guidelines, with explanations, for how and why certain license terms may or may not disqualify a license for certification as Copyfree Standard Definition compliant. It is not an exhaustive or comprehensive list; it only addresses certain common causes for copyfree standard noncompliance, about which people often have questions.
An "advertising clause" is, most specifically, a license term that requires advertising materials for a derived work or a work that incorporates the original work in some way to give credit to the original work. For instance, the Original BSD License contains this advertising clause:
3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the <organization>.
The term "advertising clause" is sometimes more broadly applied to similar requirements that do not specifically refer to advertising materials, because they serve to advertise the original work. The PHP License includes such a clause:
6. Redistributions of any form whatsoever must retain the following acknowledgment: "This product includes PHP software, freely available from <http://www.php.net/software/>".
Advertising clauses such as these violate point 3. Free Modification and Derivation of the Copyfree Standard Definition by specifying conditions (beyond licensing) that must apply to modifications.
A "bookkeeping clause", also known as a "requirement of notification", is a license term that requires downstream distributors of a work to include records of modifications made to the work or distribution actions taken in the redistributed package, or to maintain accessible records of those modifications. For instance, the Apache License 2.0 contains this bookkeeping clause in Section 4:
2. You must cause any modified files to carry prominent notices stating that You changed the files
The Python Software Foundation License Agreement for Python 2.7.3 also includes a bookkeeping clause:
3. In the event Licensee prepares a derivative work that is based on or incorporates Python 2.7.3 or any part thereof, and wants to make the derivative work available to others as provided herein, then Licensee hereby agrees to include in any such work a brief summary of the changes made to Python 2.7.3.
Bookkeeping clauses such as these violate point 3. Free Modification and Derivation of the Copyfree Standard Definition by specifying conditions (beyond licensing) that must apply to modifications.
Project Organization Clause
A "project organization clause" is a license term that imposes requirements on the organization of multi-file projects subject to the license. Such clauses typically apply to the requirement of inclusion of a specific file in a project. For instance, the Apache License 2.0 contains this project organization clause in Section 4:
4. If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License. You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.
This hefty subsection of Section 4 of the Apache License 2.0 is so extensive that the term "clause" is woefully inadequate to property describe it, and imposes a broad range of potential restrictions on modified and derivative works. The possible negative consequences of these restrictions are numerous, as in the case of combining some sources from a software project distributed under the terms of the Apache License 2.0 with those of another project whose license imposes conflicting restrictions on the way a project is organized. Other potential problems that may arise are the facts that, among other possibilities, the maintenance of such a NOTICE file may clash with the need for a file using the same filename for other purposes, or the combination of files from multiple projects in a single directory where the content of the NOTICE file is not clear in how it applies to other files (thus perhaps creating confusion about attribution or other matters).
Project organization clauses may violate points 3. Free Modification and Derivation and 4. Free Combination of the Copyfree Standard Definition by specifying conditions (beyond licensing) that must apply to modifications, derivations, or combined works.
Technology Restriction Clause
A "technology restriction clause", in some cases also called a "DRM clause", is a license term that prohibits some technologies from being combined with the licensed work, used to distribute the work, or used in conjunction with the work. In general, technology restriction clauses are intended to prohibit the use of "digital rights management" measures with a work, which is why such license terms are sometimes called "DRM clauses", but any restriction on technologies may qualify as a technology restriction clause. The Creative Commons Attribution License (CC-BY) contains a technology restriction clause:
You may not impose any effective technological measures on the Work that restrict the ability of a recipient of the Work from You to exercise the rights granted to that recipient under the terms of the License.
Technological restriction clauses in general may be used to prohibit the use of encryption technologies, broadcast distribution technologies, peer to peer filesharing technologies, certain types of display technologies, or in fact any other technology the author of the clause may desire.
DRM clauses in particular tend to have a benign purpose, but their purpose is very difficult to specify in legally binding license terms, and such clauses have not been substantively tested in court to determine their ultimate consequences. While most people might have a fairly clear idea of what "DRM" means, in the sense employed by former United States Supreme Court Justice Potter Stewart when he said he could not define hard-core pornography in clear terms, but "I know it when I see it," which has proven very difficult to use as an established precedent to make legal distinctions.
In a court of law, the common person's "I know it when I see it" judgment often holds little sway against the semantic maneuverings of legal arguments, which ultimately form the basis of judicial precedent. As such, DRM clauses must describe the conditions of a technology they intend to prohibit rather than simply labeling them "DRM" if they wish to have any hope of imposing predictable consequences on the terms of the license. Unfortunately, those definitions themselves may be far from clear in application to technological conditions of a work or its distribution that were not foreseen by the author of the license, and because of that inherent unpredictability when attempting to establish legal restrictions on technology the potential for negative unintended consequences for even the most well-meaning technology restriction clauses is nontrivial.
Furthermore, even digital rights management technologies themselves can benefit people opposed to DRM in principle, as in the hypothetical case of open source DRM technologies developed in part to help people research methods for legally circumventing commercial DRM. Using a license for materials that may be combined with such technologies for testing and other research purposes (such as example media files, documentation of DRM research, GUI toolkit software libraries, and so on) can also have a chilling effect on research in this hypothetical case.
Depending on whether the prohibited technologies are integral to a derivative version or distinct from it, a technology restriction clause violates one or both of points 3. Free Modification and Derivation and 4. Free Combination of the Copyfree Standard Definition.
Copyfree Standard Certification
Licenses that have already been certified as conforming to the Copyfree Standard Definition are listed at the copyfree.org licenses page.
You may submit a license for review if you wish it to be considered for certification as conforming to the Copyfree Standard Definition.