Research Issues
- Offline Content Protection
- Secure Home Networking
- Next Generation Optical Media Content Protection
Research Overview
Digital contents, e.g. still images, motion pictures, musics, and
text documents, have diverse applications areas, because they can be
easily copied, edited, and transmitted. On the other hand, they have
a potential problem that they may be illegally distributed and/or
used, which leads to a great loss for not only each individual user
and/or enterprise, but also content industry itself. In this
project, we do research on digital content protection, to protect
such illegal distribution and/or usage, and eventually to promote
secure content creation and distribution. In detail, our research
items consist of three issues: "Secure Home networking", secure
contents sharing and backup within home networking while protecting
the rights of the content owners, and "Next Generation Optical Media
Content Protection", protection of the illegal copying and tracing
of the illegally distributed contents for next generation optical
media such as HD-DVD and Blu-Ray."Off-line Content Protection",
off-line file protection within enterprises.
Off-line Content ProtectionWhen a user accesses data stored
in the server, he/she is usually certified by user ID, password, or
a public key cryptosystem, and data is usually transmitted after
encrypted. However, once the data is downloaded to a local storage
or a portable media, they are stored after decrypted, and possibly
accessed by someone else. The confidential information leakage
accident by the P2P application proves the fact. To prevent such
accidents, we are developing an off-line content protection system
by off-line certification, which protects all the files stored in
portable PC or portable media from unlawful access, by storing files
being encrypted, allowing decryption only for authorized users. To
achieve this, we apply "broadcast encryption" technology, which has
a good track record in a copy protection system of DVD or an SD
memory card, and is further adopted as a copy protection system of
next-generation optical media.
Secure Home NetworkingPervasion of broadband, start of
terrestrial broadcasting, and such have promoted the "home
networking", in which each family has plural of digital devices
which are connected each other. At the same time, several content
protection technologies are standardized, and one of the examples is
the "copy one generation" restriction for Japanese terrestrial
programs, effective since April, 2004. However, these restrictions
cause a problem that contents cannot be shared even within family.
In this project, we do research on a technology which allows
contents sharing and backup within each home networking while
prohibiting illegal copying and distribution outside the home
networking.
The chart below shows the overview of the secure
home networking. Contents can be shared and you can make as many
backup copies as you like within a home networking without having
the restriction of the distance. On the other hand, contents outside
the home networking are bound to existing content protection
technologies, such as CPRM and DTCP.
Secure Home Networking
Next Generation Optical Media Content Protection
Pervasion of High-Def contents are accelerated by the start of terrestrial broadcasting and
shipment of HD-DVD and Blu-Ray device and media planned in 2006. Accordingly, protection of these contents is
becoming a very important issue. In this project, we do research on the technology of
illegal copy protection and traceability of illegally distributed contents of these contents, and proposing it to
AACS-LA (Advanced Access Content System Licensing Administrator), the organization to develop and standardize
the content protection technologies on the next generation optical media.
The chart below shows the traceability technology for optical media, which we call "Sequence Key". This technology can specify the users and/or devices from which contents are illegally distributed and/or copied. This technology is adopted by
"AACS Pre-recorded Video Book Revision 0.90", issued by AACS-LA on April, 2005.
"Sequence Key", tracing technology in next generation optical media content protection
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