Difference between revisions of "4.0/Technical protection measures"

Since Version 1.0, the CC licenses have contained language prohibiting imposition of TPMs on CC-licensed works. The current language in CC BY-SA 3.0 4(a) is the following:

You may not impose any effective technological measures on the Work that restrict the ability of a recipient of the Work from You to exercise the rights granted to that recipient under the terms of the License.

(Similar language is in 4(b).)

Within the CC and libre licensing communities, this language has been controversial for a long time, in part because it potentially (and paradoxically, given the clause's purpose) limits users' freedoms and complicates use of CC-licensed material in widely used platforms that have TPMs built in.

Outside of the CC and libre licensing communities, awareness of this clause may be minimal. Reasons for this apparently include the choice not to mention this language in the license chooser and human-readable deeds.

One potential solution (the addition of a "parallel distribution" requirement) was extensively discussed, but rejected, for 3.0. For extensive review of the discussion which led up to that rejection, see Version 3#DRM.

Since the creation of the original CC TPM language, TPMs have become more commonplace. For example:

• 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. This limitation may constitute an effective technological measure on the content stored within iOS apps, so distribution of CC-licensed materials via the App Store may constitute a violation of the license. Further research on this issue would be welcome; in particular, it would be good to understand under what conditions (if ever), and to what extent, FairPlay or other TPMs in iOS "restrict the ability of a recipient ... to exercise the rights granted" by the CC licenses. A potential starting point for such research, describing various security mechanisms in iOS, including FairPlay and on-disk encryption, may be found here.

• All Japanese terrestrial broadcasting is protected by a TPM. As a result, CC Japan receives inquiries about use of CC-licensed materials in Japanese TV at least monthly, if not more frequently. CC Japan's answers to this question include the point that "you cannot use the image without creating adaptation, (or find a way not to impose TPM for the segment)." 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. Friends of CC have heard from an industry source that not imposing a TPM on a particular Japanese terrestrial broadcast is technically possible, but practically impossible. This conflict between the anti-TPM clause and digital TV was raised in 2008 Summit's Legal Day. At the time, the problem was expected but somewhat theoretical. Now that all terrestrial TV broadcasting became digital-only for most of Japan, it is real. Some at the time pointed out that TPM would not be sustainable so we could simply wait and the TPM would disappear. That prediction is not right so far.

Proposals for 4.0

For ease of reference on discussion lists, please do not alter proposal numbers.

TPM Proposal No. 1: Drop prohibition of effective technical protection measures, and add permission to circumvent, possibly using GPLv3's Sec. 3's well vetted language as closely as possible.

After several years of discussion, GPL version 3, Sec. 3 ("Protecting Users' Legal Rights From Anti-Circumvention Law") attempts to allow circumvention of TPMs that either (1) incorporate the GPL-licensed work as part of their functionality or (2) are used to restrict access to the GPL-licensed work. The actual language is as follows:

No covered work shall be deemed part of an effective technological measure ..."

When you convey a covered work, you waive any legal power to forbid circumvention of technological measures to the extent such circumvention is effected by exercising rights under this License with respect to the covered work, and you disclaim any intention to limit operation or modification of the work as a means of enforcing, against the work's users, your or third parties' legal rights to forbid circumvention of technological measures.

The GNU project offers an in-depth explanation of this clause. FSF-E has a summary of several talks on the subject by Richard Stallman and Eben Moglen, as well as drafts of earlier versions of this language here.

The first and third portions of the GPL language focus on the use of the licensed work as a functional component a TPM, rather than application of a TPM to the licensed work. Since CC-licensed works are unlikely to be a functional component of a TPM, these portions are likely inapplicable to Creative Commons licenses. Eliminating those portions leaves the following language (adjusted for terminology in CC 3.0):

When you Distribute a Work, You waive any legal power to forbid circumvention of technological measures to the extent such circumvention is effected by exercising rights under this License with respect to the Work.

Pros:

• This clause places no new obligations on the distributor, so compliance is easier when compared to a parallel distribution obligation or similar clause that requires a proactive step by the licensee.

Cons:

• Permitting circumvention is, in practice, not equivalent to ensuring access, because many TPMs may be difficult or illegal to circumvent. (For example, in Japan, such sales, manufacturing, and other acts related to circumvention device are a crime punishable up to 3 years in prison, etc., according to Art.120bis of Japanese copyright law.)

Note that a clause of this type could be used in parallel to the existing language; i.e., the license could both prohibit application of TPM and permit circumvention if a TPM was applied.

It is also possible to drop the TPM clause in only some licenses; e.g., it may make sense to make CC-BY a more "pure" "attribution is the only requirement" license by dropping the TPM provision altogether, while keeping the requirement in CC-BY-SA. For more discussion of this, see this mailing list thread, among others.

TPM Proposal No. 2: Allow parallel distribution in place of total TPM prohibition.

Pros:

• Allow copying of a digital image under CC-BY into increasingly common TPM-protected distribution channels, such as the Japanese TV programs discussed above.

Cons:

• It was explicitly rejected during the 3.0 discussion. There were a variety of reasons for this, including negative reception by CC's international affiliate teams. Version_3#DRM contains extensive review of those discussions.

Please add other TPM proposals here, and number them sequentially.

Related debate

We encourage you to sign up for the license discussion mailing list, where we will be debating this and other 4.0 proposals. HQ will provide links to related email threads from the license discussion mailing list here.

• DRM proposals for 4.0 are also discussed here.
• 2011-12 discussion on cc-community
• debate about parallel distribution on cc-licenses
• proposal for removing TPM restriction in BY on cc-licenses
• summary of DRM issue on cc-licenses

Relevant references

Please add citations that ought to inform this 4.0 issue below.