1. Field of the Invention
The present invention relates to a data recording apparatus for recording data on a record (recording, recordable or recorded) medium, a method therefor, a data reproducing apparatus for reproducing data recorded on a record medium, a method therefor and a record medium on which data has been recorded. More particularly, the present invention relates to an information providing/collecting apparatus for providing and collecting so-called multimedia information, such as video information and music information, or program information and a method therefor.
2. Related Background Art
As a data record medium on which information signals, such as Audio data, video data and various data items, are recorded, means for optically recording information signals, specifically, a so-called compact disk (CD) for use in the music field and a CD-ROM which meets the CD standard and which is used for data have been used all over the world in recent years.
Hitherto, information providing service has been realized as a so-called data base system and a personal computer communication system in each of which a user terminal (a terminal of an information collecting side) and an information provider are connected to each other through, for example, the telephone line to enable information required by the user to be taken out. Another information providing service has been realized with which a large-capacity medium, such as a so-called CD-ROM having encoded information recorded thereon is distributed and key information for decoding encoded information is transmitted to the user by, for example, communication so that encoded information recorded on the CD-ROM is decoded and decoded information is copied on a hard disk or the like so as to be used.
Moreover, a technique has been disclosed in Japanese Patent Publication No. 2-60007 in which a password formed by encoding a file key by using a code key is supplied to a computer; and a program written on the record medium is decoded by a coding mechanism to prevent copying and sharing of the software program.
Hitherto, all of information items recorded on the foregoing CD or the CD-ROM are read by a reproducing apparatus and copied onto, for example, a hard disk. Then, data copied onto the hard disk is supplied to an encoder system for the CD or the CD-ROM to newly make a CD or a CD-ROM so that a pirate edition is easily manufactured. As described above, the security function, such as the copy protection, has been unsatisfactory.
The foregoing problem is also critical for a so-called digital video disk (DVD), which is expected to be a data record medium for a next generation.
On the other hand, in the conventional information providing service, a method has been employed in which key information for decoding is transmitted to a user in such a manner that key information is transmitted by means of voice through a telephone line. Thus, key information has not been encoded particularly. However, the foregoing method has a risk in view of keeping security.
In the case where communication is employed to transmit key information, one-to-one connection is usually established. Therefore, there is substantially no risk of key information being stolen. However, in the case where key information is transmitted through a network, there arises a problem in protecting key information.
Therefore, in an information providing system, in which mediums, on each of which encoded information has been recorded in a large quantity, are distributed by the information provider; and only in a case where a user requires information to obtain from the medium, key information for decoding the code is supplied and accounting is performed, the problem in view of security when key information is transmitted results in a risk to arise in that key information can be obtained by a person except the subject user. In the foregoing case, the information providing system cannot be held. If whether or not the user is a formal user cannot be specified, there is a risk that account is put down to'another person. Also in the foregoing case, the information providing system cannot be held.
Thus, security improvement in transmitting key information from an information provider to a user and reliable specification of a user are important requirements.