Techniques for secure distribution of digital representations that combine encryption and watermarking. When a user at a client desires to download a digital representation, the user makes a request to a server for the digital representation, which encrypts the digital representation using a first k ...
The present invention provides a system to ensure security of data in a computer network system. A center certifies a public-key of user of the system and distributes a secret-key. A first system comprises the center in a network, an information provider and a plurality of users. The center identifi ...
To prevent piracy or leakage of data content, a cryptography technique and electronic watermark technique are combined together and used. In a data content supplied to a user, a user data is entered as electronic watermark by a data management center, and the data content with an electronic watermar ...
A method and an apparatus ensuring protection of digital data are provided. In addition to re-encrypting the data using an unchangeable key, the data is double re-encrypted using a changeable key. The changeable key is used first and the unchangeable key is then used, or in another case, the unchang ...
The present invention provides a process for managing data copyright in the case when a primary user produces new data by editing a plurality of original data and supplies the new data to a secondary user. A public-key and a private-key of the primary user, and a first secret-key and a second secret ...
A system for managing a digital content, particularly a digital content to which a copyright is claimed, and a system for supplying a public-key which is used in the management of the digital content are provided. The digital content management program is embedded to an operating system of a user ap ...
The present invention provides a concrete structure for applying a crypt key system to a television system, a database system or an electronic commercial transaction system or the like. This system consists of a broadcasting station, a database, a receiving apparatus, a data communication apparatus ...
A data copyright management apparatus for handling data copyrights, and data of digital cash and video conference system is provided. The data copyright management apparatus comprises a CPU, ROM, EEPROM, and RAM. The ROM, EEPROM, and RAM are connected to the CPU bus, and a system bus of a device whi ...
A data copyright management system comprises a database for storing original data, a key control center for managing crypt keys, copyright management center for managing data copyrights, and a communication network for connecting these sections. Data supplied from the database to users is encrypted ...
A data copyright management apparatus for handling data copyrights, and data of digital cash and video conference system is provided. The data copyright management apparatus comprises a CPU, ROM, EEPROM, and RAM. The ROM, EEPROM, and RAM are connected to the CPU bus, and a system bus of a device whi ...
