CC-BY 4.0 (and the related licenses with "BY" in their names, like CC-BY-SA, CC-BY-NC) includes a clause that says I must not place "additional restrictions" on the work:

No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

In that text, "technological measures" is hyperlinked to this:

The license prohibits application of effective technological measures, defined with reference to Article 11 of the WIPO Copyright Treaty.

More info.

And "More info" links to this:

All CC license versions prohibit licensees (as opposed to licensors) from using effective technological measures such as “digital rights management” software to restrict the ability of those who receive a CC-licensed work to exercise rights granted under the license. To be clear, encryption or an access limitation is not necessarily a technical protection measure prohibited by the licenses. For example, content sent via email and encrypted with the recipient's public key does not restrict use of the work by the recipient. Likewise, limiting recipients to a set of users (e.g., with a username and password) does not restrict use of the work by the recipients. In the cases above, encryption or an access limitation does not violate the prohibition on technological measures because the recipient is not prevented from exercising all rights granted by the license (including rights of further redistribution).

(bold is mine)

Does that mean that I cannot include a CC-BY licensed work, like a sound effect or clip art, in software that I distribute in DRM-protected app stores, like the iOS App Store and Steam?

  • 1
    Some people make the decision to not distribute open source software in such stores because of those restrictions. This seems to start some morals vs pragmatism debates as well. Commented Jun 24, 2015 at 5:58

2 Answers 2


Your analysis seems to be sound except:

You may be able get around this by

  • Referring to the CC media rather than including it (downloaded from the web)
  • Publishing a link (inside the app) to the CC media in an approved non-drm mechanism.
  • Including the CC media in a form that is unprotected.

Note: You CAN use DRM, you just cannot restrict the rights.


I am going to answer this by dipping down in the actual license, and some of the work that led to it.

Early on in the process to create CC version 4.0, it was objected that a too strict ban on "Technological Protection Measures - TPM" (lawyer-speak for DRM) that had been used in previous version would disallow use of CC licensed materials on too many platforms, e.g.:

  • Several popular game and media distribution platforms, such as the PlayStation and most modern digital TVs (via HDMI/HDCP), require TPMs.
  • Apple's iOS App Store app distribution platform uses the combination of FairPlay TPM (and perhaps other measures) to control use of iOS apps.
  • All Japanese terrestrial broadcasting is protected by a TPM. [...] When the image is CC-BY-ND, it is impossible to comply with the current language and broadcast CC materials over terrestrial TV in Japan. (Source.)

The concern that locking-out CC materials from these platforms would make people decide to not use the CC license, as they wanted their materials distributed through these channels, even if that gave their audience/users less freedom. If people opt to not use CC, CC loses.

However, after a very long discussion, the CC-community decided to keep the strong anti-DRM clauses of the previous versions, so also in CC ver. 4.0, there is an explicit anti-DRM-clause (sec 2(a)(4)) in ver. 4.0:

You may not [...] apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.

It uses the phrase "Effective Technological Measures". This is also lawyer-speak for DRM.

So, the license actually ban you from distributing any CC-licensed materials through re-distributions channels that use DRM, such as iOS App Store and Steam.

However, if you do this anyway, it is unlikely that CC is going to go after you for "inappropriate use of a CC license" :-).

Instead, Creative Commons has anticipated that this will probably happen from time to time. Many creators distributing on these platforms may not even be aware of the use of DRM. In order to mitigate this, the CC version 4.0 licenses explicitly allows circumvention of the DRM. In the license text, you'll find this text (sec. 2(a)(4)):

The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures.

The reason this waiver is made by the Licensor is because anti-circumvention laws are supposed to protect the owner of the copyright to the materials (i.e. the Licensor) from illegal use. "Effective Technological Measures" is not supposed to be used for other purposes, such has helping the re-distributor in locking-in customers. So only the copyright-owner can authorize DRM, and only copyright-owner can authorize circumvention of DRM.

I personally wish they had left out the explicit anti-DRM-clause and just allowed circumvention, but the anti-DRM stance is very strong in the CC community, so the explicit anti-DRM-clause is still there in CC ver. 4.0.

It should also be noted that the permit circumvention clause in CC 4.0 is the same as the one in GPLv3, and was indeed inspired by it.

  • But is a redistributor the Licensor? Section 2(a)(5)(B) still says exactly the same thing you said was in pre-4.0 versions.
    – cpast
    Commented Aug 1, 2015 at 14:33
  • @cpast. Doooh. I thought we decided to chuck that one out, but my memory must be playing tricks on me. I have read up on the mailing lists and corrected my answer. Commented Aug 1, 2015 at 15:46

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