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Patent Issued for Optical Disc, Optical Disc Recording Method, Optical Disc Reproduction Method, Optical Disc Device and Storage System

August 12, 2014

By a News Reporter-Staff News Editor at Information Technology Newsweekly -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Fujita, Shinji (Yokohama, JP); Kawamae, Osamu (Kawasaki, JP); Kurebayashi, Masaaki (Ebina, JP); Katsuki, Manabu (Yokohama, JP), filed on July 12, 2011, was published online on July 29, 2014.

The patent's assignee for patent number 8789618 is Hitachi-LG Data Storage, Inc. (Tokyo, JP).

News editors obtained the following quote from the background information supplied by the inventors: "This invention relates to an optical disc device. More particularly, the invention relates to an optical disc device and a storage system that protect information by encrypting data.

"CSS (Content Scramble System), CPRM (Content Protection for Recordable Media) and AACS (Advanced Access Content System) are known as technologies having an encryption function for protecting copyrights from illegal copies in optical disc devices

"US2008/00222095A1 (JP-A-2007-336058) (patent document 1) discloses a technology for utilizing the AACS in write-once media not capable of overwriting files. This patent document reads as follows. 'In AACS, a plurality of keys is encrypted by using a device key assigned to each device for legally recording and reproducing content and a random number generated at random, is registered to a key file with the random number and is recorded to a recording medium. To reproduce the content, the encryption key registered to this key file is decrypted by using the random number and the device key to be reproduced. The content is reproduced by using the key so decrypted and the content is reproduced.'

"The document further describes as follows. 'MKB is referred to as 'Media Key Block' and a media key Km is encrypted and recorded. The MKB records information of illegal devices, too, and the illegal devices are not allowed to take out the media key Km.' 'The MKB encrypts and saves information necessary for generating a protected area key (Kpa) and contains Revoke Information (cancel information or nullification information). In other words, a security hole exists in a certain device key set and when a licenser inhibits the use of the corresponding device key Kd, revoke information about the corresponding device key Kd is described. The device having the corresponding device key Kd is not able to solve the cipher owing to this revoke information.'"

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "Read-only optical discs such as CD (Compact Disc), DVD, BD (Blu-ray Disc), etc, have gained a wide application as distribution media of digital contents because they are suitable for mass production and have high compatibility among devices. On the other hand, recordable optical discs have been developed in the CD, DVD and BD and have been utilized as external information storage devices for PC (Personal Computer), for example, and the content protection means described above such as CSS, CPRM and AACS have been put into practical application to prevent illegal copies of the contents the copyrights of which is to be protected.

"These content protection means are directed to prevent illegal copy of the distributed media and reproduction is possible in all the devices having the content protection means mounted thereto except inhibition of reproduction for the illegal devices recognized by the licenser.

"When the optical disc is used as an external storage medium not directed to distribution, on the other hand, there are demands for limiting the devices capable of reproducing the recorded optical discs to prevent leaks of personal information and corporate secret.

"For example, there is the demand that although other optical disc devices in a predetermined storage system having a plurality of optical disc devices can reproduce the optical disc recorded by a certain one of these optical disc devices, optical disc devices outside this storage system are not allowed to reproduce the optical disc.

"When ease-of-use is taken into consideration, it is desired that authentication through a network is unnecessary during reproduction.

"It is therefore an object of the invention to provide an optical disc device capable of arbitrarily limiting optical disc devices capable of reproducing recorded optical discs without relying on the authentication by a third party.

"To accomplish this object, the invention employs the constructions described in the appended claims, by way of example.

"The invention can accomplish an optical disc device that can limit reproducible devices of recorded optical discs without relying on authentication through a network. Therefore, the invention can reinforce information protection of optical discs as removable media against leak and manipulation.

"Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings."

For additional information on this patent, see: Fujita, Shinji; Kawamae, Osamu; Kurebayashi, Masaaki; Katsuki, Manabu. Optical Disc, Optical Disc Recording Method, Optical Disc Reproduction Method, Optical Disc Device and Storage System. U.S. Patent Number 8789618, filed July 12, 2011, and published online on July 29, 2014. Patent URL:

Keywords for this news article include: Information Technology, Hitachi-LG Data Storage Inc., Information and Data Storage, Information and Data Encoding and Encryption.

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Source: Information Technology Newsweekly

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