According to Mia Garlick, to one third party who has spoken to CC, and by a close reading of the license, yes. As long as that DRM does not remove any rights the license gives the user.
Can CC work be distributed with DRM added?
Again yes, according to the same sources and with the same proviso.
Who has the right to add DRM to CC work?
According to Mia’s responses to the draft comments, possibly only the copyright holder(s?). This would mean that only the original author and authors of derivative works could add DRM. End users would not be able to.
What about Fair Use?
The CC licenses state that nothing in them is intended to reduce Fair Use. But adding DRM has the potential to reduce Fair Use in unintended ways. Any addition of DRM therefore has at least the potential to reduce Fair Use. This might mean that no DRM can be added, as any DRM removes the Fair Use rights guaranteed (although not granted) by the license.
What about noncommercial copying?
All the licenses allow at the very least noncommercial copying of unmodified work. DRM can be used to prevent this. But is this a right guaranteed by the license or merely a permission offered by it?
What does this mean for dual distribution?
Ironically, given the terms of this debate, it means that it may mean that the novel element of dual distribution would be the requirement to provide a transparent, non-DRM copy.
Should a transparent copy clause be added?
I do not like dual distribution clauses for cultural works and they do not sit well with CC’s style of remix culture licensing. It would be very difficult to get right. We would need to look at the FDL/SFDL, which have a similar requirement.
I am not a lawyer, this is not legal advice, I may not be representing people’s views correctly, this post is more an enquiry than a statement.