APPARATUS FOR DATA DISTRIBUTION, AND TERMINAL FOR DATA DISTRIBUTION

摘要

A contents server comprises a contents database that stores the data of contents encrypted with a C key and the C key. The data of contents encrypted with the C key, together with the C key, are encrypted with an M key, and sent to a user machine. In the user machine, the data of contents encrypted with the C key and the C key are stored in a storage device. For reproduction, the data of contents encrypted with the C key and the C key are sent from the storage device to an encryption/decryption section and decrypted. The user is charged on the basis of the C key. A DA code, which changes dynamically with time, is appended to the C key.