While much has been said in this journal of the DCI-NIST saga, it’s useful to recap.
The DCI specification is the cornerstone of digital cinema. It represents the intent of the six major studios to use common methods for the distribution of content and for maintaining the security of that content. DCI Compliance is mandated in equipment financing deals, and manufacturers actively strive to meet the specification.
However, a cloud was cast over the DCI specification in January by the U.S. National Institute of Standards and Technology (NIST). NIST is the organization responsible for the FIPS 140-x series of security standards, developed for “the utilization and management of computer and related telecommunications systems in the Federal government.” As a core tenement of its security specification, DCI calls for compliance to FIPS 140-2. It has been known for several years that NIST planned to transition to a revised FIPS 140-3 specification. But the impact on the industry was not clear until the past year, when NIST incorporated changes to FIPS 140-2 through a revision of the standard’s Annex A and through circulation of transition document NIST SP800-131.
With the new changes by NIST, the DCI specification was challenged in three areas:
- SHA-1 Hash is no longer allowed for digital signatures, called for by both the DCI specification and SMPTE standards.
- The method described in ANSI 9.31 cannot be used as a random number generator for generating content keys, as called for by DCI.
- The key pair used for a digital signature cannot be used for other purposes. DCI requires the re-use of the media block key pair for AES key encryption in the KDM, for establishing TLS sessions, in addition to signing security logs.
In response to comments, NIST relaxed its call for a year-end transition for items (1) and (2), introducing a deprecation period of three and five years, respectively, for use of these algorithms. Among the many entities that requested extensions was the U.S. Department of Defense. However, only DCI requested to extend the time allowed for multi-use of the media block key pair, which unfortunately did not sway NIST. Unless NIST changes its mind by year end, multi-use use of the media block key pair will no longer be allowed after December 31, 2010, in FIPS 140-2-compliant equipment. Media blocks will be required to be redesigned to carry more than one digital certificate.
The new NIST rule raises a number of issues. Clearly, the changes imposed by NIST are outside of DCI’s control. If no action is taken, the DCI specification will be in conflict with itself after December 31, rendering insignificant a document that is core to digital cinema. Among its options, DCI can render obsolete current equipment and continue to require FIPS approval, relax its requirement for FIPS approval of equipment, or develop its own security specification that maintains the status quo in equipment design and is supported by a formal testing process.
Perhaps more pertinent is that an industry still in its infancy is unprepared to address obsolescence. At the end of June, 22,000 screens have been converted out of a worldwide footprint of 150,000. Any move toward obsolescence today could trigger severe repercussions. But change is inevitable. NIST’s actions were not capricious, but calculated to maintain an effective security standard in the face of advancing computational power. Even if DCI were to part ways with NIST, it would still be faced with the eventual upgrade of its security specification. Whether it wants it or not, DCI has its work cut out for it.