An open (or free) license for a publication allows for open use, in which usage rights are defined and granted through licensing. These open licenses are standardized and internationally recognized usage rights that precisely specify how the publication may be used.

The various Creative Commons licenses (CC licenses) help rights holders align the rights to their content with their own ideas and needs, such as the requirement to attribute the author. 

As an author, you can specify how your publication may be distributed and used, thereby granting more rights than those provided for by copyright law. Granting a free license for a publication thus makes it clear to everyone how the publication may be used and provides greater legal certainty—both for authors and for those who reuse the content. For open-access publications in particular, this not only ensures optimal accessibility, visibility, and dissemination but also clearly defines the legal framework for the reuse of the research results contained in the publication.

If, as an author, you wish not only to disseminate and make your publication accessible but also to permit its use or reuse, KIT Library recommends, in accordance with the German Research Foundation (DFG), granting an open license for the publication. 

Creative Commons licenses have gained international recognition and acceptance, not only in the academic field. Based on a modular approach, a total of six different variants of an open CC license can be created using four license modules or types.

Overview of CC License Variants

• CC0: With this license, you waive your copyrights to the extent permitted by law.
• CC BY: With this license, you allow third parties to distribute and modify your work, even for commercial purposes, as long as the authors of the original are credited.
• CC BY-SA: With this license, you allow third parties to distribute and modify your work, even for commercial purposes, as long as the creators of the original are credited and any new works based on your work are published under the same terms.
• CC BY-ND: Under this license, you allow third parties to redistribute the work, including for commercial purposes, as long as it is done without modifications, in its entirety, and the original authors are credited.
• CC BY-NC: Same as CC BY, but with the restriction that redistribution must be non-commercial.
• CC BY-NC-SA: Same as CC BY-SA, but with the restriction that redistribution must be non-commercial.
• CC BY-NC-ND: Same as CC BY ND, but with the restriction that no commercial use is permitted.

Detailed explanations of the CC licensing model can be found on the official Creative Commons website.

In addition, there are other open licenses, such as the GNU Free Documentation License (GFDL) for software or the Open Database License (ODbL) for research data.