System for data copyright management using key distribution

Abstract: A data copyright management system is provided, in which a primary user edits a received data and supplies the edited data to a secondary user. The copyright management system comprises a database and a key control center, and uses a primary copyright label, a primary use permit key including a first crypt key, a secondary use permit key, a third crypt key, and a copyright management program. The primary user decrypts the copyrighted primary data, which is encrypted using the first crypt key and supplied, to plaintext using a primary use permit key obtained from the key control center and utilizes it. In case the copyrighted primary data is stored in a primary user device, it is re-encrypted using the primary use permit key. The primary user receives a secondary use permit key for editing the copyrighted primary data from the key control center and edits the copyrighted primary data. The data under editing is encrypted using the secondary use permit key and is stored. When edit has been completed, the primary user receives a third crypt key for secondary exploitation right as the secondary copyright from the key control center, encrypts the edited data using the third crypt key and distributes it to the secondary user. The secondary user receives the third crypt key from the key control center and utilizes the edited data. The third crypt key may be generated by the primary user or by the key control center.

Description: BACKGROUND OF THE INVENTION The present invention relates to a system, which manages copyright in utilization of digital data, i.e. copyrights in display, storage, copying, editing and transfer of digital data. BACKGROUND TECHNIQUE In the information- oriented society of today, satellite broadcasting using broadcasting satellite (BS) or communication satellite (CS) or cable television (CATV) broadcasting using coaxial cable or optical fiber cable are being propagated in addition to ordinary terrestrial broadcasting. In the satellite broadcasting or CATV broadcasting, which can distribute information to several tens of channels at the same time, scrambled channels for broadcasting motion pictures, sports or music programs, which cannot be viewed by comprehensive contract, are provided in addition to general non-scrambled channels, which can be viewed under comprehensive contract. To view the scrambled channel, it is necessary to subscribe for descrambling. Because the period of such subscription is usually as about one month, it is not possible to view the programs on such channels at any desired time. To solve the above problems, M. SAITO has proposed a system in JP-A 6-46419 and JP-A 6-141004, by which a user can receive a viewing permit key from a charging center through communication line and can view programs by descrambling each program, scrambled by different scrambling pattern, using the viewing permit key, and is charged for programs at the same time, and has also proposed an apparatus for such a system in JP-A 6-132916. In the above system and apparatus, a user requests for viewing the scrambled program to a charging center via communication line using a communication device. Upon receipt of the request for viewing, the charging center sends a permit key to the communication device. At the same time, the fee for viewing is charged and is collected from the user. Upon receipt of the permit key via the communication device, the user provides the permit key to a receiving device by direct means connecting the communication device with the receiving device or by indirect means such as flexible disk. The receiving device uses the permit key thus received and descrambles the program. As an application of the above system and apparatus, JP-A 6-132916 also describes a system and an apparatus, by which a tape or a disk having a plurality of data, scrambled by a different scrambling pattern respectively, recorded on it can be sold or lent, and the specific data can be utilized using a permit key supplied via IC card or the like. In the information-oriented world of today, computer communication networks are now organized to utilize the data. Such communication networks include a local network called LAN (Local Area Network), a national network called WAN (Wide Area Network) or an international network called Internet. These networks utilize various types of data, which have been stored independently by each computer in the past. On the other hand, a new technique to digitize information has been developed, by which television moving picture signals can be compressed to reduce the amount of information, which was not possible to digitize in the past because amount of information is enormously increased when digitized. For the digitization of information, a number of standards have been formulated, including H.261 standard for video conference, JPEG (Joint Photographic Image Coding Experts Group) standard for still picture, MPEG 1 (Moving Picture Image Coding Experts Group 1) standard for image accumulation, and MPEG 2 standard used for wide application from current television broadcasting to high definition television broadcasting. The digitization technique utilizing the image compression technique is not only used for television broadcasting or video image recording but also used for handling television moving picture data which could not be handled by computer. Attention is now focused on "multimedia system" as future technique, which can handle various types of data by computer and digitized television moving picture data at the same time. The multimedia system is also incorporated in data communication and is utilized as one of the data on database. With the utilization range of the database being expanded than ever, important problems arise such as the problem of how to charge the fee for data utilization from the database, the problem of copyrights related to copying or transfer of data other than those directly utilized, or the problem of secondary exploitation right associated with secondarily generated copyrights in data editing. To ensure perfect editing of charging and copyrights, it is necessary to take such measure that data cannot be utilized by those other than the authorized users, and the best means for this purpose is to encrypt the data. In the television systems or database systems as described above, a crypt key is needed to encrypt the data and to decrypt and utilize the encrypted data, and a crypt key must be delivered to the user, while the procedure is very complicated because perfect security and reliability must be assured. In the present invention, cryptology is very important. First, description will be given on the cryptography in general. In the cryptography, the encryption to encrypt a plaintext M using a crypt key K and to obtain a cryptogram C is expressed as: C = E (K, M) and decryption to obtain a plaintext M from the cryptogram C using a crypt key K is expressed as: M = D (K, C). Further, M. SAITO has proposed a concrete arrangement of a data copyright management system in JP-A 6-64889. In this system, in order to manage copyrights in display (including the process to turn to audio signal), store, copy, edit and transfer of digital data in a database system including real-time transmission of digital picture, either one or more of the program to manage the copyrights, copyright information or the copyright management message are transmitted, when necessary, in addition to a permit key to allow the user to utilize the encrypted data. When the user attempts to utilize the data other than the condition of the permission or of request, a copyright management message is displayed on the screen, notifying caution or warning to the user. The copyright management program watches and manages in such manner that no utilization of data is performed, which is against the condition of request or permission. The data is encrypted and supplied and is then decrypted using a permit key and is utilized. When the data is stored in a device, is copied to a medium other than the device, or is transferred outside the device, re-encryption is performed. Also, a permit key is provided for each utilization such as displaying/using, storing, copying, editing, transferring, etc. US 5,291,598 discloses a system to control the use of an informational product, which is processed consecutively in three different manufacture modules. The first manufacture module generates a registration code, the second manufacture module changes the operational mode of the informational product upon verification of an authorization code and stores a user record in the informational product. Each time when the informational product is activated, the third manufacture module determines the proper operational mode based on the mode stored in the user record and the identity of the executing processor. Harn et al., Computers & Security, Vol. 11 (1992) No. 8 p. 747-752 discloses a software authentication technique in order to provide protection against data corruption during electronic transmission via networks or manual distribution via disks. No copyright protection is intended. EP 709 760 A2 is only relevant with respect to novelty of the present invention as it has an older priority date than the present invention but was published after the priority data of the present invention. It discloses a data copyright management system wherein a primary crypt key is used by a user to decrypt supplied data. A second use permit key is used for editing the primary copyrighted data. After editing the edited primary copyrighted data are encrypted again by the second use permit key before storing the edited data. SUMMARY OF THE INVENTION It is an object of the present invention to provide a copyright management method wherein copyrighted primary data are not altered while they may be further edited and distributed as copyrighted secondary data. This object is solved by the method according to claim 1 and the data carrier according to claim 14. Improvements of the inventive method and data carrier are provided in the respective dependent claims. The system according to the present invention comprises a database, a key control center, a primary user, a secondary user, and a network system, which connects these with each other. A primary copyright label, a primary use permit key including a first crypt key, a secondary use permit key including a second crypt key, a secondary copyright label, a third crypt key, and a copyright management program are used. When a plaintext copyrighted primary data is supplied to a primary user, the data is encrypted using a first crypt key. When the primary user wishes to utilize the encrypted copyrighted primary data, the user requests distribution of a permit key for primary utilization via a network system to a key control center. When the request for distribution of the permit key for primary utilization is received from the primary user, the key control center sends the permit key for primary utilization to the primary user and charges the fee. Using a first crypt key including in the received primary use permit key, the primary user decrypts the encrypted copyrighted primary data In case the plaintext copyrighted primary data is stored in a device of the primary user, the data is re-encrypted using the primary use permit key. When the primary user wishes to utilize the copyrighted primary data, the primary user requests the distribution of a secondary use permit key for editing the plaintext copyrighted primary data to the key control center via the network system. The key control center sends the secondary use permit key to the primary user. Upon receipt of the secondary use permit key, the primary user copies the copyrighted primary data and edits the copy of the copyrighted primary data. When the plaintext copyrighted secondary data which is the copyrighted primary data under editing is stored in the device of the primary user, the data is encrypted using a second crypt key included in the secondary use permit key. When the final edited data is stored in the device of the primary user, the data is encrypted using a third crypt key. As a result of secondary processed data which is secondary data edition of the copyrighted data, the primary user now possesses the secondary exploitation right as secondarily generated copyright. In order to execute the secondary exploitation right, the third crypt key is registered at the key control center. The encrypted copyrighted secondary data obtained by encryption of the plaintext copyrighted secondary data using the third crypt key is sent to the secondary user by copying it to an external storage medium or by transferring it via the network system. The secondary user who wishes to utilize the encrypted copyrighted secondary data requests distribution of the third crypt key to the key control center. Upon receipt of the request for distribution of the third crypt key, the key control center sends the third crypt key to the secondary user via the network system. When the secondary user receives the third crypt key, the secondary user decrypts the encrypted copyrighted secondary data by third crypt key, and utilizes it. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of an embodiment of a data copyright management system according to the present invention; Fig. 2 is a schematical block diagram of an embodiment of a system managing data copyrights according to the present invention; Fig. 3 is a conceptual drawing for explaining limitation of primary utilization executed by a copyright management program Pc in the present invention; Fig. 4 represents a conceptual drawing for explaining limitation of utilization of data editing executed by a copyright management program Pc in the present invention; and Fig. 5 is a block diagram for explaining a process for producing new copyrighted data from a plurality of a copyrighted data as objects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the following, description will be given on an embodiment of the present invention referring to the drawings. First, description will be given on the embodiment structure of a data copyright management system according to the present invention. A system shown in Fig. 1 comprises a database 1, a key control center 2, users 3, 3, 3,....... and a network system 4, which connects these with each other. To the database 1, data is supplied from information providers (IP) 5, 5, 5,....... In some cases, the data is supplied to the user directly from the information providers 6, 6, 6,....... via the network system 4 without going through the database 1. The data utilized in the present embodiment are objects where program and data are combined together. The users 3 are not mere utilizers, but can be information providers 5 or 6, who provide secondary exploitation works, i.e. newly produced copyrighted works, by combining or modifying a plurality of copyrighted data, which they received. In the data copyright management system according to the present invention as described above, each of the copyrighted data provided from the information providers 5 and 6 is encrypted to protect the copyright. Therefore, when the user 3 received the encrypted copyrighted data, it must be decrypted to be utilized. For this purpose, all crypt keys are deposited to the key control center 2 in this system and are under the control of the key control center 2. The cryptosystem adopted by each of the information providers 5 and 6 may be freely chosen, while the cryptosystem to be used in the secondary exploitation as secondarily utilizing data and after as described later is limited to the system adopted by the key control center. The data from the database is generally utilized using personal computers, and the OS used in these personal computers must have security processing incorporated in it. For the control of crypt keys, the copyright management program is used. For the storage of the copyright management program and the crypt keys received from the key control center 2, "key cards" realized as software on memory or HDD or realized as hardware in form of a unique board, PC card, etc. are prepared as the storage area. The key control center stores the crypt keys for protection of copyright of data and for charging fees for utilization of the copyright regardless of whether the data is actually utilized or simply registered and not utilized, and controls the crypt keys by coordinating the stored keys with copyright labels. Fig. 2 represents a schematical configuration of an embodiment of a data copyright processing system according to the present invention, in which a primary user receiving data from an information provider edits the received data and supplies the edited data to a secondary user. In this system, a plaintext copyrighted primary data D1, an encrypted copyrighted primary data ED1i, a plaintext copyrighted secondary data D2, an encrypted copyrighted secondary data ED2j, a plaintext primary copyright label Lc1, a primary use permit key K1 including a first crypt key K1i, a secondary utilization permit key K2, a third crypt key K3j, and a plaintext copyright management program Pc are used. This system comprises a database 11, a key control center 12, a primary user 13, a secondary user 19, and a network system 14 for connecting these with each other. To the database 11, data are supplied from information providers 15, 15, 15,.......In some cases, the data may be supplied to the user 13 from the information providers 16, 16, 16,....... via the network system 14 or directly via an information recording medium 17 such as CD-ROM from the information providers 16 without going through the database 11. In this figure, solid lines represent paths of plaintext data, broken lines represent paths of encrypted data, and dotted lines represent paths of keys. In this system, the plaintext copyrighted primary data D1i is supplied to the primary user 13 under the the copyrighted primary data ED1i encrypted using the first crypt key K1i: ED1i = E (K1i, D1i) from the information provider 15 via the network system 14 through the database 11, or from the information provider 16 via the network system 14, or via an information recording medium 17 such as CD-ROM. The primary user 13 who wishes to utilize the encrypted copyrighted primary data ED1i thus supplied requests distribution of a primary use permit key K1 by presenting a primary copyright label Lc1 to the key control center 12 via the network system 14. Upon receipt of the request for distribution of the primary use permit key K1 from the primary user 13, the key control center 12 searches the primary use permit key K1 using the presented primary copyright label Lc1 and sends the primary use permit key K1 to the primary user 13 via the network system 14 and charges the fee at the same time. The primary user 13 decrypts the encrypted copyrighted primary data ED1i using the first crypt key K1i included in the received primary use permit key K1 D1i = D (K1i, ED1i) and utilizes it. In case the decrypted plaintext copyrighted primary data D1i is stored in a device of the primary user 13, it is re-encrypted using the first crypt key K1i ED1i = E (K1i, D1i), and the re-encrypted copyrighted primary data ED1i is stored. In case the re-encrypted copyrighted primary data ED1i is to be utilized again, the encrypted copyrighted primary data ED1i is re-decrypted and re-encrypted. The primary user 13, who wishes to edits the plaintext copyrighted primary data D1i, requests distribution of the secondary use permit key K2 for edit of the plaintext copyrighted primary data D1i to the key control center 12 via the network system 14. Upon receipt of the request for distribution of the secondary use permit key K2, the key control center 12 sends the secondary use permit key K2 to the primary user 13 via the network system 14. When the secondary use permit key K2 is received, the primary user 13 edits the plaintext copyrighted primary data D1i according to the content of the permit key and obtains the plaintext copyrighted secondary data D2j. In case the plaintext copyrighted secondary data D2j is to be stored in a device of the primary user 13, the plaintext copyrighted secondary data D2j is encrypted using the second crypt key K2: ED2j = E (K2, D2j). When the completion of the edit, the primary user 13 generates a third crypt key K3j in order to execute the secondary exploitation right for data edit of the copyrighted secondary data, and the third crypt key K3j thus generated is registered at the key control center 12. The third crypt key may not be generated by the primary user 13, but it may be prepared and distributed by the key control center at the request of the primary user 13. In case the primary user 13 copies the plaintext copyrighted secondary data D2j to an external storage medium 18 or transfers it via the network system 14, the plaintext copyrighted secondary data D2j is encrypted using the third crypt key ED2j = E (K3j, D2j), and the encrypted copyrighted secondary data ED2j is supplied to a secondary user 19. The secondary user 19, who wishes to utilize the encrypted copyrighted secondary data ED2j thus supplied, requests distribution of the third crypt key K3j to the key control center 12 via the network system 14. Upon receipt of the request for distribution of the third crypt key K3j from the secondary user 19, the key control center 12 sends the third crypt key K3j to the secondary user 19 via the network system 14. When the third crypt key K3j is received, the secondary user 19 decrypts the encrypted copyrighted secondary data ED2j using the third crypt key K3j D2j = D (K3j, ED2j) and utilizes it. In case the encrypted copyrighted secondary data ED2j is to be utilized again, the encrypted copyrighted secondary data ED2j is decrypted and encrypted using the third crypt key K3j. In the following, detailed description will be given on acquisition of the copyrighted primary data, primary utilization of the copyrighted primary data, edit of the copyrighted primary data to the copyrighted secondary data, supply of the edited copyrighted secondary data, and utilization of the copyrighted secondary data. In this system, a plurality of plaintext copyrighted primary data D1i are supplied to the primary user 13 with the encrypted copyrighted primary data ED1i using the first crypt key K1i ED1i = E (K1i, D1i) together with the plaintext primary copyright label Lc1 directly from the information provider 16 or via the database 11. The copyright management program Pc manages the use of the copyrighted data by the user. More concretely, the copyrighted data is decrypted and re- encrypted using crypt key and utilization of the copyrighted data is restricted according to the content of the use permit key. In this system, a plaintext primary copyright label Lc1 to be utilized for acquisition of crypt key is attached to the encrypted data ED1j. In other words, the encrypted copyrighted primary data ED1j comprises a plaintext copyright label Lc1 and the encrypted copyrighted primary data ED1i. On the plaintext primary copyrighted label Lc1, title of the data and name of the application program used and the name of the primary copyright owner, etc. are entered. The primary user 13 who wishes to utilize the encrypted copyrighted primary data ED1i thus supplied requests distribution of the primary use permit key K1 by presenting the plaintext primary copyright label Lc1 to the key control center 12 via the network system 14. After confirming that the primary use permit key to be distributed is the key K1 using the presented primary copyright label Lc1, the key control center 12 sends the primary use permit key K1 thus confirmed to the primary user 13 via the network system 14. When the primary use permit key K1 is received, the device of the primary user 13 is turned to copyright management mode, and the primary user 13 is now entitled to utilize the copyrighted primary data. Because the first crypt key K1i is included in the primary use permit key K1, the first crypt key K1i is not recognized by the primary user 13. On the other hand, the key control center 12 charges and collects the fee and identifies the status of use of the copyrighted data and the status of utilization of database of the primary user 13. Fig. 3 is a conceptual drawing for explaining restriction of the primary utilization by the copyright management program Pc in the present invention. Similarly to the invention described in Japanese prior application No. 6 - 64889, the primary utilization of the data obtained in the data copyright management system of the present invention is limited to ordinary utilization, i.e. direct utilization of the data and output including printing of utilization results, and it is not allowed to copy the data to an external storage medium or to edit and transfer via a network system or in principle, to store the data inside the device. However, it is possible to store the data with encrypted. It is needless to say that the data D other than the copyrighted data can be displayed, printed, stored, copied, edited or transferred by the application program in use. In this figure, reference numeral 21 represents a storage unit such as a non-volatile semiconductor memory or a hard disk drive incorporated in a device 20 of the primary user, reference numeral 22 represents a display unit for output, 23 represents a printing unit for output, D1 represents a copyrighted primary data, D represents a non-copyrighted general data, 24 represents a secondary user, to whom the data is supplied by copying via flexble disk or CD-ROM or by transferring using a network system. In this figure, solid lines represent processing routes permitted, and broken lines show processing routes not permitted. The encrypted copyrighted primary data ED1i acquired by the primary user 13 from external information providers 15 or 16 either directly or via the data base 11 is incorporated with a plaintext primary copyright label Lc1 supplied together-with and is stored in a storage unit 21 of the primary user device 20. The primary user 13 who wishes to utilize the encrypted copyrighted primary data ED1i stored in the storage unit 21 refers to general description of the encrypted copyrighted primary data ED1i and a plaintext primary copyright label Lc1 shown information of application program used by the encrypted copyrighted primary data ED1i using the copyright management program Pc, and identifies the using environment of the encrypted copyrighted primary data ED1i such as presence or absence of an application program used for preparation of the encrypted copyrighted primary data ED1i. As a result, it is judged that the encrypted copyrighted primary data ED1i can be utilized. When the primary user 13 inputs request for the use of the encrypted copyrighted primary data ED1i to the copyright management program Pc, the copyright management program Pc starts the application program used by the encrypted copyrighted primary data ED1i and reads the encrypted copyrighted primary data ED1i from the storage unit 21 to memory in the primary user device 20. On the other hand, the plaintext copyright label Lc1 is sent to the key control center 12, and the primary use permit key K1 is supplied to the primary user in accordance with the processing flow already described. The encrypted copyrighted primary data ED1i is decrypted to the plaintext copyrighted primary data D1i, using the first crypt key K1i included in the primary use permit key K1 D1i = D (K1i, ED1i), and it can be used by the started application program. In case the plaintext copyrighted primary data D1i on memory of the primary user device 20 is to be stored in the storage unit 21, the plaintext copyrighted primary data D1i is re-encrypted using the first crypt key K1i ED1i = E (K1i, D1i), and it is stored. The storage includes producing and storing temporary file for data maintenance. In case the re-encrypted data ED1i is to be re-used, re-decryption and re-encryption are performed using the first crypt key K1i. The utilization other than displaying and printing, storage or editing, i.e. copying to an external storage medium or transfer to other device, of the plaintext copyrighted primary data D1 or the encrypted copyrighted primary data ED1i are prohibited by the copyright management program Pc. As already described, in the data copyright management system of the present invention, the utilization of the obtained copyrighted data is limited to ordinary modes of utilization, i.e. direct utilization by displaying the data on the display unit 22 or output of the utilization results by the printer 23. Copying of the data to an external storage medium or transfer of the data to the secondary user 24 via the network system and editing the data are prohibited by the copyright management program. Therefore, it is not allowed to cut and paste a part of the copyrighted primary data D1i to the other data D or to cut and paste a part of the other data D to the copyrighted primary data D1i. The copyrighted primary data D1i can be stored to the storage unit 21 exceptionally if it is in the encrypted state using the first crypt key K1i, but it cannot be stored in case it has been edited. In the data copyright management system of the present invention, distinguishing the copyrighted primary data D1 from general data D and determing as to whether the copyrighted data has been edited or not are performed by the copyright management program Pc. Computer file comprises a data file main unit and a management table entered attributes of the data file. Therefore, by investigating the management table, it can be judged whether the file is the copyrighted data or not. On this management table, data file size and date and time of produced are entered. By investigating these in the management table, it can be judged whether the file has been edited or not. When stored in the storage unit 21, the copyrighted primary data D1i is to be encrypted and coupled with the primary copyright label Lc1. When the data is decrypted and is read on memory, the copyrighted primary data D1i and the primary copyright label Lc1 are separated from each other by the copyright management program, and the separated copyright label Lc1 is managed by the copyright management program Pc. The copyright management program watches by which application program the copyrighted primary data D1i is used and prohibits "cut and paste" of the copyrighted primary data D1i to the non-copyrighted general data D and "cut and paste" of the non-copyrighted general data D to the copyrighted primary data D1i. Fig. 4 is a conceptual drawing for explaining restriction of utilization in the data editing executed by the copyright management program Pc in the present invention. The primary user 13 who wishes to edit the plaintext copyrighted primary data D1i, in the primary utilization, notifies the key control center via the network 14 that the plaintext copyrighted primary data D1i is to be edited and requests distribution of the secondary use permit key K2 necessary for the edit of the plaintext copyrighted primary data D1i to the key control center 12 via the network system 14. Upon receipt of the request for distribution of the secondary use permit key K2 from the primary user 13, the key control center 12 sends the secondary use permit key K2j to the primary user 13 via the network system 14. As a result, the primary user device 20 of the primary user 13 is turned to edition mode, and the primary user 13 can edit the encrypted copyrighted primary data ED1i. The primary user 13 decrypts the encrypted copyrighted primary data ED1i to the plaintext copyrighted primary data D1i using the first crypt key K1i and displays it on the display unit 22 and edits the data. To protect the copyright of the copyrighted primary data at first, the plaintext copyrighted primary data D1i for editing is copied, and the plaintext copyrighted primary data D1i' for edit obtained by this copying is edited. The primary user 13 decrypts the encrypted copyrighted primary data ED1i to the plaintext copyrighted primary data D1i to display on the display unit 22, and before editing, copies the plaintext copyrighted primary data D1i for edit and edits the plaintext copyrighted primary data for edit D1i' obtained by copying. In case the plaintext copyrighted primary data for edit D1i' or the plaintext copyrighted primary data D1i" under editing is to be stored in the primary user device of the user 13, encryption is performed using the secondary use permit key K2 ED1i' = E (K2, D1i') or ED1i" = E (K2, D1i"), and it is stored as the encrypted copyrighted primary data ED1i' or as the encrypted copyrighted primary data ED1i". As the encrypted copyrighted primary data ED1i is stored in the storage unit 21 without being edited, by comparing its management table with file size, produced date and time of the plaintext copyrighted primary data for edit D1i' or D1i" which has been edited, it is judged whether the file is the edited file or not. When edit of the data has been completed, the data is produced to a plurality of new plaintext copyrighted secondary data D2j, and secondary exploitation right as secondary copyrights is newly generated on the data D2j. To protect the secondary exploitation right, the primary user 13 who edited the plaintext primary copyrighted data D1i requests distribution of the third crypt key K3j to the key control center 12. Upon receipt of the request for distribution of the third crypt key K3j, the key control center 12 sends the third crypt key K3j to the primary user 13 via the network system 14. When the third crypt key K3j is received, the primary user 13 encrypts the plaintext copyrighted secondary data D2j using the third crypt key K3j ED2j = E (K3j, D2j), and the encrypted copyrighted secondary data ED2j is stored in the storage unit 21 of the primary user 13. In case the encrypted copyrighted data ED2j is to be utilized, decryption and encryption are performed using the third crypt key K3j. In the plaintext copyrighted secondary data D2j edited by the primary user 13, secondary exploitation right in data edition of the primary user 13 is present in addition to the primary copyright of the plaintext copyrighted primary data D1i before editing and owned by the information provider. To execute the secondary exploitation right, the primary user 13 sends information such as title of the data, name of the application program used, outline of the content, name of the primary copyright owner, etc. together with the third crypt key K3j to the key control center 12. The key control center stores and controls these together with the third crypt key K3j. On the other hand, the primary user 13 supplies the encrypted copyrighted secondary data ED2j to the secondary user 24 by copying it to an external storage medium 18 or by transferring it via the network system 14. The secondary user 24 who wishes to utilize the supplied encrypted copyrighted secondary data ED2j requests distribution of a use permit key including the third crypt key K3j to the key control center 12. The utilization of the plaintext copyrighted secondary data D2j using the use permit key including the third crypt key K3j is limited to general utilization of the plaintext copyrighted secondary data D2j or to storage to the user device, and it is not allowed to copy the plaintext copyrighted secondary data D2j or the encrypted copyrighted secondary data ED2j to an external storage medium 18, to transfer it to a third user via the network 14, or to edit the plaintext copyrighted secondary data D2j. As described above, the copyrighted data handled in the present invention is directed to "object" where program and data are integrated, and the object can be processed as parts-like through computer programming or various types of processings. Description will be given now on the case where new copyrighted data is prouced utilizing a plurality of copyrighted data that are the objects, referring to Fig. 5 and Fig. 2. In Fig. 5, reference numerals 31, 32 and 33 represent copyrighted primary data D11, D12 and D13 which comprise objects respectively. By utilizing the copyrighted primary data D11, D12 and D13, the new copyrighted secondary data D2j represented by 30 is produced. The utilization of the copyrighted data D11, D12 and D13 include three editorial forms: utilization of whole parts such as the copyrighted data D11 shown by reference numeral 34; utilization of a part such as the copyrighted data D12' as shown by reference numeral 35; and utilization after modifying such as the copyrighted data D13' as shown by reference numeral 36. The copyrighted data are edited by linking in object-unit, referring, embedding and combining them. Such embedding and combining can be performed freely. Also, it is possible to add other matters to the copyrighted data 37, which has been thus embedded and combined. The newly produced copyrighted data D2j in this way consists of objects assembly. In the plaintext copyrighted secondary data D2j thus produced, secondary exploitation right of the primary user 13 who has produced newly arises in addition to the copyright of the copyrighted primary data D1i. To execute the secondary exploitation right, it is necessary to encrypt the plaintext copyrighted secondary data. For this purpose, the primary user 13 prepares the third crypt key K3j and encrypts the plaintext copyrighted data D2j using the third crypt key K3j ED2j = E (K3j, D2j), and the encrypted copyrighted data ED2j is supplied to the secondary user 19 by copying it to an external storage medium 18 or by transferring it via the network 14. In order that the tertiary user can easily receive the third crypt key K3j, the third crypt key K3j is registered at the key control center 12. By registering the third crypt key K3j, the secondary exploitation right of the primary user 13 is recorded at the key control center 12. In this case, those sent from the primary user 13 to the key control center 12 at this time includes, in addition to a plurality of the third crypt keys K3j of which number corresponds to the produced plural copyrighted secondary data, the number of the third crypt keys K3j, the second crypt key K2j, the copyrighted primary data used, information of the other copyrighted data to which the copyright management program is linking, access path to the copyrighted data used, application program used by the copyrighted data used, and explanation of the copyright works. The secondary user 19 who wishes to utilize the encrypted copyrighted secondary data ED2j thus supplied requests distribution of the third crypt key K3j to the key control center 12. Upon receipt of the request for distribution of the third crypt key K3j, the key control center 12 sends the third crypt key K3j to the secondary user 19 via the network system 14. The secondary user 19 receives the third crypt key K3j, decrypts the encrypted copyrighted secondary data ED2j using the third crypt key K3j, and utilizes it. When the third crypt key K3j is received, the copyright management program Pc attaches the copyright label Lc2j to each copyrighted data D2j so that the secondary user can utilize it. At this time, the linkage with the copyrighted data, which is the object linked with the newly produced copyrighted data, is released. At the time of the release of the linkage, the entity of the copyrighted primary data, which has had so far relationship as the linkage only, is embedded into the encrypted copyrighted secondary data ED2j, and allows to distribute as a copyright work only through ED2j file. In this case, if the encrypted copyrighted secondary data ED2j is to be utilized again, decryption and encryption are performed using the third crypt key K3j. The key control center sends back the third crypt key K3j to the requester and charges and collects the fee according to the copyright labels Lc1 and Lc2. The copyright owner of the copyrighted data can change access path of own copyrighted data by applying to the key control center. The copyright owner of the copyrighted data can also edit (modify) own copyrighted data using the third crypt key K3j and also can register it using another key.

Claims: A data copyright management method with the steps: sending copyrighted primary data ED1i encrypted by a first crypt key K1i from a database 11 to a primary user 13; transmitting a first use permit key K1 including said first crypt key K1i from a key control center 12 to said primary user 13; decrypting said encrypted copyrighted primary data ED1i by using said first crypt key K1i and performing primary utilization of the copyrighted primary data D1i by said primary user 13; transmitting a second use permit key K2 from said key control center to said primary user 13 ; copying said copyrighted primary data D1i; and performing edit on said copy of said copyrighted primary data D1i using said received second use permit key K2 by said primary user 13; encrypting said data being under editing to be stored by said second use permit key K2; obtaining copyrighted secondary data D2j when editing is completed; and encrypting said copyrighted secondary data D2j by a third crypt key K3j and storing, copying or transferring the encrypted copyrighted secondary data ED2j. A data copyright management method according to claim 1, wherein said second use pemit key includes a second crypt key therein; comprising the step: encrypting said copyrighted primary data under editing by using said second use permit key, to be stored. A data copyright management method according to claim 1 or 2, comprising the steps: obtaining copyrighted secondary data by editing said copyrighted primary data and encrypting said copyrighted secondary data by using a third use permit key, to be stored. A data copyright management method according to claim 3, comprising the step transferring said encrypted copyrighted secondary data to a secondary user. A data copyright management method according to claim 3 or 4, comprising the steps: preparing said third crypt key by said primary user and transmitting said third crypt key from said primary user to said key control center. A data copyright management method according to claim 3 or 4, comprising the steps: preparing said third crypt key by said key control center and transmitting said third crypt key from said key control center to said primary user. A data copyright management method according to claims 1, 2, 3, 4, 5 or 6, comprising the step: adding a non-encrypted primary copyright label to said encrypted copyrighted primary data. A data copyright management method according to claim 1, comprising the steps: presenting said primary copyright label by said primary user to said key control center, before transmitting said first use permit key from said key control center to said primary user. A data copyright management method according to claim 1, comprising the steps: presenting said primary copyright label by said primary user to said key control center, before transmitting said second use permit key from the key control center to said primary user. A data copyright management method according to claim 6, comprising the steps: presenting said primary copyright label by said primary user to said key control center, before transmitting said third krypt key from the key control center to said primary user. A data copyright management method according to claim 3, comprising the step adding a non-encrypted secondary copyright label to said encrypted copyrighted secondary data. A data copyright management method according to claim 10, comprising the step. presenting said secondary copyright label to said key control center by said primary user; and transmitting a third crypt key from said key control center to said primary user. A data copyright management method according to one of the preceding claims characterized in that it is run as a data management program (Pc) on a computer. A Data carrier for use in the method of one of claims 1 to 12 characterized by carrying a data management program (Pc) executing a method according to one of claims 1 to 12 when run on a computer. A Data carrier according to the preceding claim, characterized in that it carries the management program (Pc) and crypt keys.

Inventors: OKAZAKI SHOICHI, SAITO MAKOTO, OKAZAKI, SHOICHI, SAITO, MAKOTO
Applicants: MITSUBISHI CORP, MITSUBISHI ELECTRIC CORP, MITSUBISHI CORPORATION, MITSUBISHI ELECTRIC CORPORATION
Application year: 1996
Main classification: H04L9
IPC codes: H04N7, G06F21, H04N5, G06F1, G11B20, G09C1, G06Q50, G06F12, G06Q10, H04L9