A memory card 110 extracts a session key Ks from the data applied onto a data bus BS3 by carrying out a decryption process. An encryption processing unit 1406 encrypts a public encryption key KPcard(1) of memory card 110 based on session key Ks, and applies the encrypted key to a server via data bus BS3. A memory 1412 receives from a server data such as license key Kc, license ID data License-ID and user ID data User-ID encrypted with a public encryption key KPcard(1) differing for each memory card for storage, and receives encrypted content data [Dc]Kc encrypted with license key Kc from data bus BS3 for storage.