The popular concept of Trusted Device List is a list of digital certificates of trusted equipment, along with the physical location of the device. Such a list is of value to those charged with the creation of KDMs. Without this list, security key management is impossible.
In the DCI spec, TDL has a slightly different meaning: that of a list of digital certificates of trusted equipment placed inside the KDM. The KDM is already targeted for a specific media block, so a KDM configured with a TDL, therefore, would have the additional limitation of only working with certain projectors. While some security conscious execs still like this idea, most are fearful of triggering a wave of dark screens if this feature is actually put to work.
In late 2004, recognizing that the management of security keys would become a major problem, your author began socializing a scheme for carrying out such management based on a concept called Facility List Message. No problem so large could be visible to only one person, and certainly DCI’s own security consultant was concerned. But neither had any success in convincing DCI to incorporate the concept in its pending specification, so NATO undertook the effort and drove the creation of SMPTE 430-7 Facility List Message, without the benefit of its support in the DCI spec.
At the time, it would be safe to say that studios were more concerned with the concepts behind security key management rather than the mechanics. Today, they’re still concerned with the concepts. Few have taken concrete steps towards promoting the mechanics. Fox’s effort with FLM-x (the standardized FLM with standards-allowed extension elements added) and the secret (but not sure why it’s secret) FLM with extensions promoted by Disney.
In 2004, the popular concepts lacked imagination or an understanding of commercial considerations. In 2010, sadly, the popular concepts lack imagination or an understanding of commercial considerations. The popular concept, that of a worldwide central database called Trusted Device List (TDL), is likened to the concept of a worldwide currency. While a worldwide currency would somewhat simply travel (and get rid of those nasty currency conversion fees on credit cards), it poses huge problems for regional economies. But for those who do not understand economics, a single worldwide currency probably sounds like a reasonable thing to promote. Ergo, the centralized TDL.
The concept of centralized TDL has roots in both Orwell and Tolkein, with a little Marx tossed in. As one former member of DCI skeptically called it: “one ring to rule them all.” But even if the centralized TDL were to exist, mechanics must then be considered.
To populate a TDL, one needs to know the security details of the equipment, and where it is located. Most TMS systems attempt to collect this information, either through manual entry by theater operators, or automatically by cooperative equipment. Once this information is gathered, it can be collected by the governing deployment entity. KDM creators such as Deluxe and Technicolor can then collect information from the deployment entity. For the cases where a deployment entity does not exist, things become messier. Using Deluxe and Technicolor as the example consumers of this information, they each end up making direct contact with exhibitors to collect the information. In some cases, they may even agree to split up territories and share information to cut down on the expense of collecting it.
To populate a centralized TDL, a business entity would need to exist to duplicate the efforts described of Deluxe and Technicolor. More than likely, the central entity will not create KDMs, as KDM creators have special trust relationships with studios. So the central entity will not replace Deluxe or Technicolor in the KDM role. The question then arises as to who pays for the service provided by the central entity. No doubt, studios will say that Deluxe and Technicolor will pay. And, of course, we know the response that will emanate from Deluxe and Technicolor. So much for the centralization of TDL.
Take away the centralized nature of the TDL business, however, and a very sensible problem remains to be solved: that of reliably populating TDL databases maintained by commercial KDM creators. To do so at the lowest cost requires automation. That takes us back to discussions of FLM and CCM. CCM stands for Cinema Communication Message, a companion concept to FLM and KDM that was never fully developed for lack of funds.
The means to develop digital cinema has shifted dramatically over the past decade. Had not DCI been formed and funded, had not NATO engaged in standards, and had not the many companies seeking to build products cooperatively banded together in standards committees, digital cinema would never have moved forward to the position it is in today. But all of that love has changed. Without funding to back their concepts, studios and exhibitors are without the ability to push agendas forward. Left to commercial interests having little motive to work together, full TDL automation could take another decade to complete.