CONTENT DATA REPRODUCTION SYSTEM AND RECORDING DEVICE

摘要

An illegal device is excluded from a system, thereby preventing illegal use of content data. A memory card (10) contains a service key (Ksrv) for ciphering content key data (Kc) in a secret area (14). The memory card (10) ciphers, using the service key (Ksrv), data relating to answer data (Ac) obtained when providing question data (Q) to a host function (F) of a normal host device (20), and contains the ciphered data. Providing the question data (Q) to the host device (20), the answer data (AH) is obtained on the basis of the question data (Q) and the host function (F). A comparison part (122) judges whether the answer data (AH) and the answer data (Ac) match or not. When match, the memory card (10) deciphers the content key data (Kc) ciphered using the service key (Ksrv).