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?
Can I redistribute CC-BY works in DRM-protected app stores?
creative commons;cc by;drm