Av data transmission apparatus, av data reception apparatus, and av data transmission and reception system

An AV data reception apparatus which receives from an AV data transmission apparatus, encrypted AV data and usage control information indicating a usage restriction, said AV data reception apparatus comprising:

• an AV data reception unit configured to receive the encrypted AV data;
• a decryption unit configured to decrypt the encrypted AV data;
• a cipher-type-information reception unit configured to receive cipher type information indicating a cipher scheme used for encrypting the AV data;
• and
• a decryption key switching unit configured to switch a decryption key to another decryption key generated under a decryption key generation scheme associated with the cipher type information,
• wherein, when said cipher-type-information reception unit receives cipher type information associated with predetermined usage control information indicating prohibition of use of the AV data in an AV data reception apparatus which does not support the predetermined usage control information, said decryption unit is configured to perform decryption under a cipher scheme indicated by the received cipher type information, using a decryption key generated under a decryption key generation scheme associated with the predetermined usage control information, based on the received cipher type information.

An AV data transmission and reception system comprising:

• at least one AV data reception apparatus which receives encrypted AV data;
• and
• an AV data transmission apparatus which transmits, to said at least one AV data reception apparatus, the encrypted AV data and usage control information indicating a usage restriction,
• wherein said AV data transmission apparatus comprises:
• an encryption unit configured to encrypt AV data;
• an AV data transmission unit configured to transmit the encrypted AV data;
• a cipher-type-information switching unit configured to switch cipher type information indicating a cipher scheme used for encrypting the AV data, to other cipher type information;
• and
• a cipher-type-information transmission unit configured to transmit cipher type information to said at least one AV data reception apparatus,
• wherein said encryption unit is configured to encrypt AV data under a first cipher scheme, the AV data being prohibited from being used in a first AV data reception apparatus that does not support predetermined usage control information and permitted to be used in a second AV data reception apparatus that supports the predetermined usage control information,
• said AV data transmission unit is configured to transmit the AV data encrypted under the first cipher scheme to said first AV data reception apparatus, and
• said cipher-type-information transmission unit is configured to transmit to said first AV data reception apparatus, the other cipher type information switched by said cipher-type-information switching unit, the other cipher type information indicating a second cipher scheme which differs from the first cipher scheme and does not allow said first AV data reception apparatus to perform decryption, and
• said at least one AV data reception apparatus comprises:
• an AV data reception unit configured to receive the encrypted AV data;
• a decryption unit configured to decrypt the encrypted AV data;
• a cipher-type-information reception unit configured to receive cipher type information indicating a cipher scheme used for encrypting the AV data;
• and
• a decryption key switching unit configured to switch a decryption key to another decryption key generated under a decryption key generation scheme associated with the cipher type information,
• wherein, when said cipher-type-information reception unit receives cipher type information associated with predetermined usage control information indicating prohibition of use of the AV data in an AV data reception apparatus which does not support the predetermined usage control information, said decryption unit is configured to perform decryption under a cipher scheme indicated by the received cipher type information, using a decryption key generated under a decryption key generation scheme associated with the predetermined usage control information, based on the received cipher type information.