CC licences are based on four basic terms:
Attribution (BY): You must always provide credit to the original author.
Share-Alike (SA): If you remix, transform, or build upon the material, you must distribute your contributions under the same licence as the original.
Non-Commercial (NC): You may not use the material for commercial purposes.
No-Derivatives (ND): You may not distribute modified versions of the work.
All six CC licences require that users provide attribution (BY) to the creator when the material is used or shared.
Attribution CC BY
The most permissive of the Creative Commons licences which allows for maximum dissemination and use of the licenced work. The licence permits others to use, reproduce, disseminate or display the article in any way, including for commercial purposes as long as they credit the author for the original creation. It can also be used in digital research such as data mining and long-term preservation independent of publishers.
Major funders currently only accept the CC BY licence as compliant with their policy.
Creative Commons — Attribution 4.0 International — CC BY 4.0
Attribution-ShareAlike CC BY-SA
The licence lets others remix, tweak, and build upon the work even for commercial purposes, as long as they credit the copyright holder and licence their new creations under the identical terms. CC BY-SA is the recommended licence for teaching materials.
Creative Commons — Attribution-ShareAlike 4.0 International — CC BY-SA 4.0
Attribution-NoDerivatives CC BY-ND
The licence allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to the copyright holder.
Creative Commons — Attribution-NoDerivatives 4.0 International — CC BY-ND 4.0
Attribution-NonCommercial CC BY-NC
This licence lets others remix, tweak, and build upon a work non-commercially, and although their new works must also acknowledge the copyright holder and be non-commercial, they do not have to licence their derivative works on the same terms.
Creative Commons — Attribution-NonCommercial 4.0 International — CC BY-NC 4.0
Attribution-NonCommercial-ShareAlike CC BY-NC-SA
The licence lets others remix, tweak, and build upon a work non-commercially, as long as they credit the copyright holder and licence their new creations under the identical terms.
Creative Commons — Attribution-NonCommercial-ShareAlike 4.0 International — CC BY-NC-SA 4.0
Attribution-NonCommercial-NoDerivatives CC BY-NC-ND
The most restrictive of the six main licences, only allowing others to download works and share them with others as long as they credit the copyright holder, but they can’t change them in any way or use them commercially.
Creative Commons — Attribution-NonCommercial-NoDerivatives 4.0 International — CC BY-NC-ND 4.0Note that CC licences including term NonCommercial (NC) are problematic concerning open access, because it is difficult to determine commercial usage, for example ResearchGate can be considered as commercial usage. Use of this licence may also restrict research collaboration with companies.