Meaning: Appropriate authorship and rights information must be provided. This means that the author or authors, the source, and the licence (including reference/link) of the work must be given. It must also be stated whether and, if so, how changes have been made.

Consequence and problem: Attribution is mandatory. Each of the licences requires appropriate authorship and rights statements when the licensed work is used. This may lead to complicated authorship and rights statements in the case of multiple derivative works.

Note: With CC0, Creative Commons also offers the option of waiving the condition of attribution. This is appropriate for marking works for which no copyright protection is possible or given from the outset, and for works that one would like to release into the public domain. This can be useful for certain types of research data, among others. You can find more on this in the frequently asked questions (below).