A memory card performs decryption processing to extract a session key from data applied from a server to a data bus over a cellular phone network. An encryption processing unit encrypts a public encryption key of memory card based on a session key, and applies the same to the server via data bus. A register receives and stores data such as a decrypted license ID and a user ID from the server, and a memory receives and stores encrypted content data applied from a data bus and encrypted with a license key.