creative-commons attribution
CC-BY Layers of people
<p>How does the attribution part of the CC license work when you have people copying from a third party source? For example, if Person A posted a video on a website under the license CC-BY, Person B finds it and uses it in his video (crediting Person A), and Person C finds Person B's video and uses Person A's section in his own video. Who should Person C credit? Person A or Person B? How do I make it so that they have to credit the first person who made it, instead of Person C crediting Person B crediting Person A?</p>

<p>Would this aspect be the same with CC-BY-SA?</p>

<p>PersonB has to attribute PersonA and, if possible, provide a link to PersonA’s work. In the typical case, PersonC would just follow this link and use PersonA’s work directly. But let’s assume this is not possible (e.g., because PersonA’s site is down).</p>

<p>If PersonB has modified PersonA’s work, PersonB has to state this. So unless PersonC finds such a statement, it can be assumed that no modifications were made. </p>

<p><strong>Without modifications:</strong> PersonC takes PersonA’s work that is included in PersonB’s work. PersonC has to attribute PersonA (and not PersonB).</p>

<p><strong>With modifications:</strong> The license <a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow"><em>CC BY</em></a> doesn’t require PersonB to license their work under <em>CC BY</em>, too. So depending on PersonB’s license choice (or choice not to use any license), it could be the case that PersonC is not allowed to use PersonA’s work that got modified by PersonB. In case PersonB chooses to use <em>CC BY</em>, too, PersonC has to attribute both, PersonA and PersonB.</p>

<p>For the license <a href="https://creativecommons.org/licenses/by-sa/4.0/" rel="nofollow"><em>CC BY-SA</em></a>, it works the same in case no modifications were done. In case PersonB modified PersonA’s work, PersonB has to license it under <em>CC BY-SA</em>, too, so PersonC has the right to use Person B’s work (based on PersonA’s work), and PersonC has to attribute both.</p>

<p><strong>tl;dr</strong>: You attribute who has created or modified the work, not who has distributed it.</p>

<p>See also the CC FAQ <a href="https://wiki.creativecommons.org/index.php/Frequently_Asked_Questions#Do_I_need_to_be_aware_of_anything_else_when_providing_attribution.3F" rel="nofollow">Do I need to be aware of anything else when providing attribution?</a></p>

<blockquote>
  <p>[…] Additionally, when you are using a work that is an adaptation of one or more pre-existing works, you may need to give credit to the creator(s) of the pre-existing work(s), in addition to giving credit to the creator of the adaptation.</p>
</blockquote>
