Apparatus for data copyright management system

A data copyright management apparatus is used with a user terminal and comprises a CPU, a CPU bus, ROM, EEPROM, and RAM. The CPU, ROM, EPROM, and RAM are connected to the CPU bus, and a system bus of a device which utilizes the data can be connected to the CPU bus. A data copyright management system program, crypt algorithm, and user information are stored in the ROM, and a second private-key, a permit key, a second secret-key, and copyright information are stored in the EEPROM. A first public-key, a first private-key, a second public-key, and a first secret-key are transmitted to the RAM during the operation. The data copyright management apparatus may be configured in the form of a monolithic or hybrid IC, a thin IC card, PC card, and insertion board which have a unique terminal. If a copyright management program is supplied from the external, the it is stored in the EEPROM, otherwise it is stored in the ROM. In addition to a microprocessor of user terminal which decrypts encrypted data for displaying and processing and re-encrypts the decrypted data for storing, copying, or transferring, at least one microprocessor, desirably two microprocessors, are added for decrypting and re-encrypting data which is encrypted and supplied. The microprocessors to be added may be connected to a system bus of the microprocessor of the user terminal, it is desirable that a multiprocessor configuration is implemented by using a SCSI bus, PCI bus, or SCI bus. Apparatus for decryption and re-encryption may be configured separately or as a unit. Device which is used to input and output encrypted data may be connected directly to the apparatus for decryption and re-encryption. The data copyright management apparatus may be implemented in the form of a monolithic IC, a hybrid IC, or a built-in subboard, and the apparatus in these forms is incorporated in a computer, television set, set-top box, digital video tape recorder, digital video disk recorder, digital audio tape apparatus, or personal digital assistants, and the like.