The present invention relates to an information processing apparatus by which a communication channel providing a high degree of privacy is established between a PDA and a data communication server. Data encrypted with a temporary key is shared by a PDA and a memory card The memory card decrypts the data by the shared temporary key, and then stores the data in the memory card. Data encrypted with a temporary key shared by a PC and the memory card The PC decrypts the data by the shared temporary key, and then stores the data in the PC. The PC and the data communication server are connected to each other, and perform mutual authentication. The data encrypted with a temporary key shared by the PC and the data communication server as a result of the authentication is transmitted from the PC to the data communication server via a broadband network.