Digital interface debate resurfaces at Western show
eet.com
By Junko Yoshida and George Leopold
EE Times
(12/04/98, 2:56 p.m. EDT)
ANAHEIM, Calif. — A battle over a copy-protected digital interface
resurfaced here at the Western Show this week, pitting five companies led
by consumer giant Sony Corp. against a separate group of electronics
manufacturers spearheaded by Thomson Consumer Electronics and Zenith
Electronics Corp.
On the Sony team, known as 5C, are Hitachi, Intel, Matsushita and Toshiba.
The five have developed what they call the industry's first encryption-based
IEEE 1394 link layer, called the Digital Transmission Content Protection
Method (DTCP).
Zenith and Thomson are promoting a smart-card-based renewable encryption
scheme called Extended Conditional Access, or XCA, which the partners
have submitted to a Consumer Electronics Manufacturers Association
(CEMA) panel reviewing copy-protection schemes.
The encryption-enabled digital interface is a pivotal piece of technology that
would link digital cable or satellite set-tops, VCRs, DVD players and PCs to
digital TV sets. The interface would prevent unauthorized copying of digital
programming.
The renewed cross-industry bickering over the incompatible DTCP and XCA
schemes could slow resolution of the DTV-cable interface issue. The debate
prompted regulators last summer to press the cable and consumer-electronics
industries to work things out quickly, out of fear that the issue could slow
introduction of digital TV in the United States.
Uncertainty about encryption could also have implications for other digital
consumer products beyond cable set-tops. For instance, Sony and Quantum
Corp. last week demonstrated a new audiovisual technique for storing TV
programs on a hard drive. Without an industry agreement on a universal
interface and encryption scheme, Quantum's new storage device won't be
linked to some DTV receivers.
Sony and other companies that have played key roles in developing DTCP
for the 1394 interface claim their technology has already been approved by
multiple industries, including PC makers, consumer-electronics firms and
Hollywood studios. Further, Sony has developed functional silicon by
implementing a DTCP-based encryption and a key-exchange method. Sony
said its chip will be commercially available next spring.
DTCP grew directly out of the digital transmission discussion group within
the Copy Protection Technical Working Group, an ad-hoc cross-industry
group, said Scott Smyers, vice president of the Interconnect Architecture
Laboratory at U.S.-based Sony Electronics. "Our new 1394 link-layer chip is
designed to meet all the requirements set by the Motion Picture Association
of America (MPAA)," Smyers added.
Specifically, he said the chip responds to MPAA's request for installing
"some means of authentication" in the digital interface so that two digital
consumer devices can legitimately copy digital content.
An MPAA spokesman in Washington said the "5C [proposal] is a great start.
We won't consider it the Rosetta Stone just yet." He added, "We've never
said there is one standard way to go about" copy protection.
Thomson and Zenith, meanwhile, insist that nothing is settled in the digital
copy-protection debate. "The 5C copy-protection scheme may give the
impression that it has gone several steps ahead of our XCA proposal," Paul
Snopko, director of electronic systems R&D at Zenith (Glenview, Ill.), said
here last week. "But in reality, no digital-consumer products exist on the
market yet" with either competing encryption scheme. "In that sense, we are
still at the same starting line," Snopko said.
Howard Mirowitz, vice president of Mitsubishi Electric America (Sunnyvale,
Calif.), agreed that different industry groups are offering alternatives to the
five-company copy-protection scheme. Matsushita is believed to be looking
for a copy-protection plan for an analog-component interface, and a separate
group is promoting a different copy-generation management-system
approach, Mirowitz said.
The Thomson-Zenith scheme is designed for both one- and two-way digital
interfaces, and uses a renewable security system. Specifically, XCA could be
used with a one-way digital interface like the EIA-762 RF remodulator
standard as well as the IEEE 1394 interface.
By contrast, DTCP has been specifically designed for 1394. The
DTCP-enabled 1394 link may be "a good solution for an $8,000 digital TV,
but would you want the same expensive 1394-based digital interface for a
kitchen TV?" Snopko asked. Thomson and Zenith described their approach
as "a simple, elegant and cost-effective solution designed for a range of
different digital consumer products."
Sony and its partners, meanwhile, argue that the 1394 interface was chosen
for its inherent two-way communication capability. "MPAA has demanded
that we install both encryption and authentication mechanisms in the digital
interface," an industry source said. That requirement left the 5C group no
choice but to use 1394, the source said.
The Sony camp remains skeptical about the smart-card-based renewable
security approach proposed by XCA backers. They wonder how the
approach could succeed in the United States, where, as one source said,
"smart cards were raised and shot down so many times already."
The 5C team is also concerned about the cost of renewable security. The
group said it remains unclear who would pay for a new smart card for each
digital device, at a cost of as much as $50 per display device.
Snopko and others stressed that a number of satellite decoders and cable
set-top boxes are already equipped with a smart-card slot, even though they
may not be widely used yet in the United States. Smart cards will likely be
paid for by service providers tied to specific encrypted services, proponents
said.
Thomson and Zenith believe they are building momentum for their proposal
by working with CableLabs, the cable industry's research arm, and by
submitting it to a CEMA engineering panel called Working Group 2. The
group was formed to evaluate the impact of different architectures for
protecting copyrighted digital content on consumer-electronic devices.
A spokeswoman for CEMA (Arlington, Va.) said the group will continue
seeking industry proposals for copy protection until the end of December
while soliciting a list of requirements from MPAA and other video, audio and
software providers on the types of protection features they want in digital
consumer products.
The spokeswoman said multiple solutions are possible, and that CEMA will
likely let the market decide which is best. Working Group 2 is scheduled to
complete a report on the copy-protection issue by the end of January.
It remains unclear for now exactly what kind of support the XCA group can
expect from the cable industry. David Robinson, senior vice president and
general manager of digital network systems at set-top maker General
Instrument Corp. (Horsham, Pa.), said GI is committed to using the 1394
interface for its digital set-tops. He predicted XCA would only play an
interim role.
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