Syunji Harada

Encryption apparatus for ensuring security in communication between devices

Data transmitter, data transmitting method, data receiver, information processor, and information recording medium

Communication device which performs two-way encryption authentication in challenge response format

Data reception apparatus, data transmission apparatus, information processing system, data reception method and information record medium storing the data reception method suitable for preventing illegal copy of documents

Information devices whitch select and use one out of a plurality of encryption utilization protocols for protecting copyrights of digital productions

Message receiving apparatus and message transmitting apparatus

Data copying system and method, data reading apparatus, data writing apparatus and data recording medium for optionally preventing a third generation digital copy from a ROM disc

Authentication apparatus according to the challenge-response principle

Contents delivery method, and server, terminal and computer program therefor

Method and apparatus for mutual authentication according to the challenge/response principle