The present invention relates to a method and system for managing access to data by utilizing management information embedded in the data. More particularly, it relates to embedding management information into data through data transformation without changing the amount of data and managing access to the data, based on this management information, when the data is accessed.
With the spread of multimedia environments, systems handling digital information, such as digital video disks (DVDS), digital video cameras (DVCs), digital CS satellite broadcasting, and internets, are becoming still more popular. Also, the development of apparatuses that can process and transfer very large quantities of multimedia data at high speed has advanced. However, it depends upon the number of applications for attraction contents such as theater movies whether or not the aforementioned apparatuses will be spread from now on. No matter how excellent hardware may be, the spread of the hardware would be difficult unless a large quantity of contents that attracts the purchasing desire of customers are distributed.
What becomes problematic at this time is the protection of works. For example, digital video disks have a sufficient hardware based method in the distribution of theater movies, however, for problems with protection of contents, particularly with illegal duplication (copy), there have been no methods provided such as suppliers of contents can satisfy. This is because, although the contents of digital data can be easily duplicated and changed, there is provided no effective specification to prevent such action. Thus, it is the current status that many attractive contents cannot be expected to be distributed with these media. In fact, since such problems with copyright have not been solved, digital video cameras have only been sold as exclusive machines for photographing. Thus, effectively protecting digitized works is indispensable for a further spread of multimedia, and the development of such protection techniques and the generation of normalized standards have been expected.
One of conventional attempts to control duplication of digital contents such as music is to adopt a copy generation management system (CGMS) signal in digital audio tape (DAT). The CGMS signal is constituted by two bits of data and represents the following duplication conditions.
The aforementioned method writes the two data bits in a predetermined place of data format. When duplication of data is performed, the aforementioned CGMS signal is detected at the side of a receiver. If the content of the signal represents duplication inhibition, the receiver stops the duplication of the content. However, this written place can be easily specified and the content can also be easily written over, so it is easy for users to overwrite the content of this signal. That is, it is difficult in the conventional technique to effectively prevent the illegal duplication of contents because it has various disadvantages such that
it is an approach to append data management information separate from the data: and
it is easy to identify where is the management information.
Hence, there has been a desire for the development of techniques that can effectively control access to digital contents and effectively prevent illegal duplication.
In view of the aforementioned problems, the objective of the present invention is to provide a system that is capable of controlling access to data and effectively preventing illegal access to data or the like.
To attain such objective, there is provided an access management information embedding system for preparing management information for managing access to data, and embedding the management information in the data through data transformation not changing amount of data, wherein the management information embedded through data transformation not changing amount of data is extracted in managing access to the data, access to the data being managed according to the extracted management information. In addition, management of access to the data is varied according to the type of medium in which the data is stored such as RAM (rewritable type), R (write once type) or ROM (read-only type). In addition, the management information is arranged to contain information for controlling recording of the data, reception of the data, playback of the data, interference of output of the data, duplication history of the data, or modification of the management information.
Controlling recording of the data means that, when the management information is embedded in data contained in a medium such as a CD-ROM, the content of the CD-ROM is permitted or inhibited to be duplicated in another medium such as a digital video disk.
Controlling reception of the data means that, when the management information is embedded in data incoming over, for example, radio wave or a network, the data is received by a receiver, and permitted or inhibited to be output from the receiver.
Controlling playback of the data means that, when the management information is embedded in data contained in a medium of a type such as a RAM (rewritable type) or R (write-once type), the data is permitted or inhibited to be reproduced.
Controlling interference of output of the data means that, when the management information is embedded in data contained in a medium of a type such as a RAM or R, the data is permitted or inhibited to be output outside, or output interference is controlled by superimposing noise on an output signal.
Controlling duplication history of the data means that, for example, when the management information embedded in the data contains information allowing duplication only once, after duplication is performed once, additional information for inhibiting duplication other than the management information is added to the management information, whereby further duplication or playback is controlled by the management information and the additional information.
Controlling modification of the management information means that, for example, when the management information embedded in the data contains information allowing duplication only once, after duplication is performed once, the management information itself is modified to inhibit further duplication.
Although the management information relates to recording, duplication, reception, playback, duplication history, output interference or the like of the data, the present invention controlling access based on the content of embedded management information in accessing the data can be appropriately applied to other management such as restriction on access equipment, restriction of access users, deadline for use of data, and authentication information without departing from the spirit of the invention.
xe2x80x9cEmbeddingxe2x80x9d used herein means to hide specific information through deformation of data itself by using data hiding technique or the like. Here, data hiding is a generic term of technique for embedding information in another medium (still image, audio, motion image, or the like). Unlike encryption, the technique does not aim how to hide information, but how to integrate information in a medium in which it is embedded.
One of the important features of data hiding lies in that it is an invisible marking technique. Since it is not to add a data bit when information is embedded in a medium, but the information is embedded by manipulating existing data so that it cannot be perceived by human visual sensation (data transformation), there is no increase in the total amount of data due to embedding of additional information. For example, the storage side can handle one type of medium through embedding of text or audio information in an image. One of the other features includes indivisibility of the embedded information. Since the data hiding directly embeds additional information in the data structure of the medium, not in a header or a separate file, the embedded information can be extracted as long as the quality of the original data is saved even if the platform of the medium or the data format is changed.
The present invention is an invention relating to a method and system for managing access to data by utilizing management information embedded in the data with use of such data hiding technique or the like. It should be noted that the access management method according to the present invention is not limited to a specific data hiding technique, but any technique can be utilized as is as long as it embeds information through data transformation without changing amount of data.