Content data reproduction system and recording device

Abstract

To exclude any unauthorized device from a system and thereby prevent illegal use of content data, a memory card 10 stores a service key Ksrv for encrypting content key data Kc in a hidden area 14 . The memory card 10 stores answer data A C to be obtained when question data Q is fed to a host function F possessed by an authorized host device 20 , with encryption applied to the answer data A C by the service key Ksrv. When the question data Q is provided to the host device 20 , answer data A H is obtained based on the question data Q and the host function F. A comparison unit 122 judges match or mismatch of the answer data A H and the answer data A C . When they match, the memory card 10 decrypts the content key data Kc encrypted by the service key Ksrv and sends it to the host device 20.

1 .- 5 . (canceled) 
     
     
         6 . A medium comprising first key information (Ksm) and unique authentication information,
 the medium comprising a storing unit that stores encrypted secret key data, the encrypted secret key data being generated by encrypting secret key data using unique key information, the unique key information being obtained by a process using the first key information.   
     
     
         7 . A device comprising a first area as a hidden area, a second area and a third area,
 wherein a session key shared between the device and a host may be generated by authentication and key exchange (AKE),   and wherein data transmission and reception may be performed between the device and the host after encryption using the session key.   
     
     
         8 . A host configured to generate a session key by authentication and key exchange (AKE) using information stored in a first area as a hidden area, a second area and a third area, the session key being shared between the host and an external device, wherein in a communication between the host and the external device using the session key, one way function or the like is applied thereto, and data converted in an irreversible manner is used for authentication. 
     
     
         9 . A content data reproduction system comprising a host,
 the host being configured to generate a session key by authentication and key exchange (AKE) using information stored in a first area as a hidden area, a second area and a third area, the session key being shared between the host and an external device,   wherein in a communication between the host and the external device using the session key, one way function or the like is applied thereto, and data converted in an irreversible manner is used for authentication,   the host further includes a first conversion unit that receives the session key data obtained by an authentication process between the host and the external device, and first output data to obtain first conversion data, and   the external device further comprises a second conversion unit that receives the session key data and second output data to obtain second conversion data, and a comparison unit that compares the first conversion data and the second conversion data to judge a match between the first output data and the second output data.   
     
     
         10 . The content data reproduction system according to  claim 9 , wherein
 the host is configured to perform an executing program for executing calculation by a host function possessed by the host.   
     
     
         11 . The content data reproduction system according to  claim 9 , wherein a part of the executing program is provided in form of a dynamic link library.