By virtue of the progress in the Internet and digital information communication networks, each user can now easily access network information through an individual-oriented terminal using a cellular phone or the like.
In digital information communication, information is transmitted through digital signals. For example, each user can transfer music and video information in the aforementioned digital information communication network without degradation in audio quality and picture quality.
It will be a system useful to the copyright owner if appropriate fees can be collected for distribution of content data such as copyrighted works of music and video information through the disseminating digital information communication network.
In such digital information communication networks, there is a possibility of the rights of the copyright owner being significantly infringed by a flood of replicates of copyright information within the digital information network unless some appropriate measures to protect the copyright are taken when content data corresponding to copyrighted works such as music and video information is to be transmitted.
Therefore, in distributing content data such as music or copyright information to allow reproduction of such content data through the digital information communication network, authentication with respect to the apparatus requesting distribution will become necessary.
It is also necessary to accommodate the possibility of the contents of such authentication procedures being obtained by a third party through fraudulent means to allow an improper user to receive distribution through the digital communication network.
Furthermore, it is necessary to prevent music data, once received by an appropriate user, from being replicated without restriction in a reproducible state.