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20 years of Creative Commons licenses

Creative Commons licenses are a standardized way to grant copyright permissions, thereby allowing third parties to use a work for specific purposes. Thus, these licenses are of great importance for open access.

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Creative Commons licenses celebrate anniversary

20 years ago, in December 2002, the American non-profit organisation Creative Commons released its Creative Commons licenses (CC licenses) for use and the occasion is celebrated!

Due to their easy handling and high flexibility, these licenses have spread worldwide: "There is no other standardised licensing system for scientific publications that is widely used in a comparable way," German science organisations commented in their appeal for the use of open licenses in science (2014). With their function of making copyrighted 'creative' content available to the public as a 'commons', CC licenses support the open access idea: making scientific literature permanently accessible and re-usable for all people, free of charge and without barriers.

Design and use

Fig. 1: The three layers of CC licenses. Source:

The success of CC licenses rests on three pillars:

First, on their compatibility with national copyright systems. This allows authors to release their publications for subsequent use in a legally secure manner and retain the copyright by granting non-exclusive rights to publishers.

Secondly, on a unique three-layer design in which the legal license agreement is linked to 'human-readable' image icons and to 'machine-readable' HTML code. This helps decisively to make CC licenses easy to use even without in-depth knowledge of copyright law.

Thirdly, on their modular structure. Thanks to a modular principle, authors can adapt the licenses to their needs and decide which access rights they want to grant to third parties. In the spirit of open access, they retain control over their work.

Four license modules are available:

Fig. 2: Possible combinations of CC licenses. Source: Brettschneider: Licensing Data, 2020,, <10.5281/zenodo.3865203>.
  • BY - Attribution: In the case of use, the name of the author must be mentioned and - as far as technically possible - a hyperlink to the original material must be provided.
  • SA - Share Alike: Adaptations are allowed, but their distribution is only permitted under the same license.
  • ND - No Derivatives: The work must remain complete and unaltered.
  • NC – Non-Commercial: Further use is only permitted for non-commercial purposes.

These modules can be combined into six licenses. Decisive for the selection is whether, firstly, adaptations may be shared and, secondly, commercial use is permitted:

Fig. 3: Creative Commons icons for CCO and CC PDM, source: Creative Commons., .

In addition, Creative Commons provides a CC0 license ('CC Zero') to make copyrighted content 'public domain', i.e. to grant unconditional release. In contrast, the Public Domain Mark developed by Creative Commons is merely a label to identify works that are not (or no longer) protected by copyright.

Using CC licenses is very simple: Creative Commons provides a generator that guides the author through the selection process and generates the corresponding license logos, including the link to the license text, as HTML code for inclusion on websites and makes them available for 'copy and paste'.

When the licensed work is subsequently used, it is mandatory to refer to the authorship and the CC license linked to the license text. Likewise, the author must be asked for any use that goes beyond the license granted. An exception are the rules of permission ("limitations") of copyright law according to which users of copyright-protected works are entitled, such as the right of citation.

CC licenses in open access

Fig. 4: open access conformity of all CC licenses, source:

An important paradigm according to the Berlin Declaration on the Open Access to Knowledge in the Sciences and Humanities (2003) states that open access content may be used and further processed in the sense of a freely accessible representation of knowledge "in any digital medium for any responsible purpose". The CC BY license guarantees this high degree of visibility and opens up the best possibilities for subsequent use and CC BY-SA permit such use too.

The CC0 license can only be recommended for open access with one restriction: Although it optimally promotes re-use, it does not require attribution. Authors are thus not visible. In contrast, licenses with NC and ND components do not correspond to the open access paradigm, although they are also frequently used in open access publications. The use of the NC component in particular is problematic. On the one hand, because there is legal uncertainty about the demarcation between commercial and non-commercial use, and on the other hand, because private universities, non-profit educational institutions and other actors in science and education are dependent on remuneration, i.e. they operate in the commercial sphere, and are thus not allowed to use material under NC licenses.

CC licenses sometimes reach their limits in the case of publications that are made openly accessible via the green route (self-archiving): If the authors have transferred exclusive rights to the publisher and use the right of self-archiving according to Section 38 of the German Copyright Act (Section 38 UrhG) or are allowed to use the publisher's PDF for self-archiving, CC licenses cannot be granted. The self-archived publication can then be labeled with the note 'in copyright' and a link to

Otherwise, however, CC licenses are ideally suited to providing comprehensive legal protection for the efficient re-use of research results in the spirit of open access.


All online resources were accessed on 01.12.2022.