Alice licensed her work under CC0 1.0.

May Bob take Alice’s work and publish it under another Creative Commons license (e.g., CC BY-SA)?

If yes, may Bob publish it under his own name (i.e., not noting that Alice authored and published it under CC0), so that users would attribute him? (Of course users wouldn’t have to follow the rules from CC BY-SA, because the work is still also licensed under CC0; assuming that Bob didn’t make any modifications.)

The CC FAQ "May I apply a Creative Commons license to a work in the public domain?" says that it "should not" be done. So that means it may be done, right?

Would this depend on Alice’s and/or Bob‘s jurisdiction?

5 Answers 5


Bob can relicense it under any license he wishes.

Taking credit for Alice's work is another thing. In jurisdictions that hold up moral rights, Bob can't. The moral rights cannot be given up by Alice, so they are still intact. What consists moral rights differs a bit, but proper attribution is usually included. In jurisdictions without moral rights, copyright law may not prevent Bob from doing it, but depending on the situation, other laws may be in place, maybe something against fraud.

  • 2
    Also, it's worth noting that, although Bob can relicense it however he wants to, it's kind of meaningless. That's Bob giving permission for something you don't need bob's permission for.
    – Daniel
    Commented Jan 16, 2017 at 21:37
  • 1
    However Bob can for instance release a project as GPL that uses CC0 code without making any statement about the original license and/or author, effectively restricting the rights of anyone who gets it via Bob's project from using it in a closed source project, while if the person/company found Alice's original CC0 release, they would not be restricted from doing so.
    – 3D1T0R
    Commented May 29, 2018 at 2:35

The CC0 license is essentially a public domain dedication. Looking at the license deed, it does not depend on jurisdictions, as it waives all rights normally provided under the copyright law by the legal authorities of the jurisdiction.

Bob can take Alice's work freely, but Alice will still retain any moral rights that is entitled to her. You don't legally have to attribute Alice.

If yes, may Bob publish it under his own name (i.e., not noting that Alice authored and published it under CC0), so that users would attribute him? (Of course users wouldn’t have to follow the rules from CC BY-SA, because the work is still also licensed under CC0; assuming that Bob didn’t make any modifications.)

Well, yes you can, but consider the author's moral rights. In some jurisdictions, this include the right to be attributed properly, and this is a legal requirement.

Therefore, to answer the question: yes, bob can relicense Alice's work, but must respect the moral rights of Alice, which can vary by jurisdiction.


There's no legal requirement [in the USA] that the CC0 license and authorship information be retained. The only risk that I know of for claiming someone else's CC0 material as your own is that you might be publicly shamed for it.

As an experiment, I ("Alice") released some code under CC0 on Stack Overflow several months ago.

Here's the license as I applied it:

/* rgbtobgr565 - convert 24-bit RGB pixels to 16-bit BGR565 pixels

Written in 2016 by [Alice < [email protected] >]

To the extent possible under law, the author has dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty. See http://creativecommons.org/publicdomain/zero/1.0/.


Then I simply waited to see what would happen. Until now, nothing happened. Today, I found that the same code just with some minor changes and with all the CC0 license information removed and replaced with a GPL license and a "Written by [Bob]" line that claims authorship by another individual.

Now, I don't see a problem with the relicensing nor with removing the attribution. But claiming authorship is problematic. In some jurisdictions and in most academic circles, that's frowned upon.

I suppose I should not be surprised how it has turned out so far.

FOLLOWUP: After a little discussion, this particular case ended satisfactorily. "Bob" has added a one-line attribution, not legally required but a nice thing to do, within the body of his code:

// This part was under CC0 Licenses and was written by [Alice]

The answers so far assume that it is definitely unmoral to not attribute work published with CC0 and it will be seen as such at court (given appropriate jurisdictions). I assume we are only talking about relicensing the work and not about using it as part of e.g. a thesis where you have to assure that it is your own work.

While I absolutely agree it is stupid to relicense the work unmodified and should not be done, the CC0 is not a CC-BY with attribution to "the public". And I certainly do not want that someone has a bad feeling about not attributing my work published as CC0 when using it as part of a larger work, because I actually wanted to enable this use case and do not want to force an attribution (otherwise I would have used a CC-BY).

It is very difficult to decide about moral, but there are always corner cases not prevented by your license that might or might not be seen as moral. Another example: It is definitely within the terms of the CC0 to use the work in commercial products (otherwise one could have used a CC-NC). So why should it not be allowed to sell this commercial product and become a millionaire (and not you)?

If you try to restrict every case that is unmoral in your eyes (or even in the eyes of most people), you will also restrict many use cases that you want to allow. You probably do not want a license that sounds like "You can use it for whatever you want, but include an attribution unless you added at least 100 lines of code yourself and do not use it in commercial products to become a millionare, but if it helps you to get food that is ok..." It would be a nightmare to maintain large open source code bases and would certainly restrain the growth of the open source software community.

When working with open source it is not unusual to find someone who is taking advantage of work you have done (for prestige or money) without explicitly giving you anything back. But that is the whole point with open source: Not to pay for every small piece of work someone has done, but working together for increasing the overall well-being.


When you hear "license," think "permission."

Can Bob give you permission to use something that you already have permission to use?

Yeah, but you didn't really need his permission, so it's pretty pointless, now isn't it?

  • 2
    Might not be "pointless" for Bob: Bob’s intention could be that others don’t realize that the work is in the public domain, so they think Bob is the author and they think that they have to attribute Bob.
    – unor
    Commented Jan 16, 2017 at 22:37
  • Right. It's pointless in the legal sense, but it's potentially misleading/fraudulent. I just wanted to clear up confusion that users of Alice's code are not actually subject to Bob's rules.
    – Daniel
    Commented Jan 17, 2017 at 23:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.