Patent ID: 8290158

Claim:
An AV data transmission apparatus for transmitting, to AV data reception apparatuses, usage control information indicating a usage restriction, and AV data in which the usage control information is embedded, said AV data transmission apparatus comprising: a circuit; 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 between cipher type information indicating cipher schemes used for encrypting the AV data; and a cipher-type-information transmission unit configured to transmit the cipher type information to the AV data reception apparatuses, wherein when first usage control information is switched to second usage control information, said cipher-type-information switching unit is configured to switch from first cipher type information corresponding to the first usage control information to second cipher type information corresponding to the second usage control information and indicating a second cipher scheme different from a first cipher scheme, the first usage control information corresponding to a first AV data reception apparatus and a second AV data reception apparatus that are included in the AV data reception apparatuses, the second usage control information corresponding to the second AV data reception apparatus and not the first AV data reception apparatus, and the first and second cipher schemes each being used for encrypting the AV data, said encryption unit is configured to encrypt the AV data under the second cipher scheme, said cipher-type-information transmission unit is configured to transmit the second cipher type information to the first AV data reception apparatus and the second AV data reception apparatus, said AV data transmission unit is configured to transmit the encrypted AV data encrypted under the second cipher scheme to the first AV data reception apparatus and the second AV data reception apparatus, the first AV data reception apparatus is permitted to use AV data in which the first usage control information is embedded and is capable of decrypting AV data encrypted under the first cipher scheme, and the first AV data reception apparatus is prohibited from using AV data in which the second usage control information is embedded and is incapable of decrypting AV data encrypted under the second cipher scheme, and the second AV data reception apparatus is permitted to use AV data in which the first or second usage control information is embedded and is capable of decrypting AV data encrypted under the first cipher scheme and AV data encrypted under the second cipher scheme.