Information recording device, information playback device, information recording medium, information recording method, information playback method, and program providing medium

An information playback device comprising:

• a memory unit containing data, including encrypted content data, a block permission table defining memory-access content data of a plurality of data files, and an integrity check value for the block permission table generated based on a memory unit identifier, the memory unit having a data storage area comprising a plurality of blocks, each block of the plurality of blocks comprising a plurality of sectors each sector of the plurality of sectors of each block of the plurality of blocks having a predetermined data capacity;
• a processing unit for reading encrypted content data portions which together comprise encrypted content data of the plurality of data files, wherein, for each data file of the plurality data files, a first portion is read from a first sector of one of the plurality of blocks, and a second portion is read from a second sector of one of the plurality of blocks, and wherein each first sector of each of the plurality of blocks is encrypted using a first encryption key, and each second sector of each of the plurality of blocks is encrypted using a second encryption key that is different from the first encryption key, and for reading a security header corresponding to the encrypted content data of the plurality of data files from at least one header block of the plurality of blocks, wherein the at least one header block is different from each one of the blocks in which the content data of the plurality of data files is stored;
• a cryptosystem unit for performing sector level decryption by using a first decryption key to decrypt data read from the first sector of each of the plurality of blocks and using a second decryption key that is different from the first decryption key to decrypt data read from the second sector of each of the plurality of blocks;
• and
• an integrity checking unit for checking the integrity of the block permission table based on the integrity check value generated based on the memory unit identifier,
• wherein the security header read from the header block includes each encryption key used to encrypt each encrypted content data portion read from each of the plurality of blocks.

An information recording method comprising the following steps performed by a control unit:

• dividing content data of a plurality of data files into separate content data portions;
• storing the separate content data portions, a block permission table defining memory-access control information, and an integrity check value for the block permission table generated based on a medium identifier, to a memory medium having a data storage area comprising a plurality of blocks, each block of the plurality of blocks comprising a plurality of sectors each sector of the plurality of sectors of each block of the plurality of blocks having a predetermined data capacity, for each data file of the plurality data files, a first portion is stored in a first sector of one of the plurality of blocks, a second portion is stored in a second sector of one of the plurality of blocks, and a security header corresponding to the content data of the plurality of data files is stored in at least one header block of the plurality of blocks that is different from each one of the blocks in which the content data of the plurality of data files is stored;
• encrypting, prior to storing, the content data portions by performing sector level encryption using a first encryption key to execute encryption of each first sector of each of the plurality of blocks, and using a second encryption key that is different from the first encryption key to execute encryption of each second sector of each of the plurality of blocks;
• and
• performing an integrity check of the block permission table based on the integrity check value generated based on the medium identifier,
• wherein the security header stored in the header block includes each encryption key used to encrypt each content data portion stored in the sectors of the plurality of blocks.

An information playback method comprising the following steps performed by a control unit:

• reading encrypted content data portions, which together comprise encrypted content data of a plurality of data files, a block permission table defining memory-access control information, an integrity check value for the block permission table generated based on a medium identifier, and a security header from a memory medium having a data storage area comprising a plurality of blocks, each block of the plurality of blocks comprising a plurality of sectors each sector of the plurality of sectors of each block of the plurality of blocks having a predetermined data capacity, wherein, for each data file of the plurality data files, a first portion is read from a first sector of one of the plurality of blocks, and a second portion is read from a second sector of one of the plurality of blocks, and wherein each first sector of each of the plurality of blocks is encrypted using a first encryption key, and each second sector of each of the plurality of blocks is encrypted using a second encryption key that is different from the first encryption key, and the security header, corresponding to the encrypted content data of the plurality of data files, is read from at least one header block of the plurality of blocks, wherein the at least one header block is different from each one of the blocks in which the content data of the plurality of data files is stored;
• decrypting the content data portions stored in each of the sectors by performing sector level decryption by using a first decryption key to decrypt data read from the first sector of each of the plurality of blocks and using a second decryption key that is different from the first decryption key to decrypt data read from the second sector of each of the plurality of blocks;
• and
• performing an integrity check of the block permission table based on the integrity check value generated based on the medium identifier,
• wherein the security header read from the header block includes each encryption key used to encrypt each encrypted content data portion read from each of the plurality of blocks.

A non-transitory computer-readable recording medium comprising a computer program product for performing, when executed by a processor, a data encryption method comprising:

• dividing content data of a plurality of data files into separate content data portions;
• storing the separate content data portions, a block permission table, an integrity check value for the block permission table generated based on a memory unit identifier, and a security header in a memory unit having a data storage area comprising a plurality of blocks, each block of the plurality of blocks comprising a plurality of sectors each sector of the plurality of sectors of each block of the plurality of blocks having a predetermined data capacity, for each data file of the plurality data files, a first portion is stored in a first sector of one of the plurality of blocks, a second portion is stored in a second sector of one of the plurality of blocks, and a security header corresponding to the content data of the plurality of data files is stored in at least one header block of the plurality of blocks that is different from each one of the blocks in which the content data of the plurality of data files is stored;
• encrypting, prior to storing, the content data portions by performing sector level encryption using a first encryption key to execute encryption of each first sector of each of the plurality of blocks, and using a second encryption key that is different from the first encryption key to execute encryption of each second sector of each of the plurality of blocks;
• and
• checking the integrity of the revocation list and the block permission table based on the integrity check value generated based on the memory unit identifier,
• wherein the security header stored in the header block includes each encryption key used for each sector of the plurality of blocks.

A non-transitory computer readable recording medium comprising a computer program product for performing, when executed by a processor, a data decryption method comprising:

• reading encrypted content data portions, which together comprise encrypted content data of a plurality of data files, a block permission table defining memory-access control information, an integrity check value for the block permission table generated based on a memory identifier, and a security header from a memory having a data storage area comprising a plurality of blocks, each block of the plurality of blocks comprising a plurality of sectors each sector of the plurality of sectors of each block of the plurality of blocks having a predetermined data capacity, wherein, for each data file of the plurality data files, a first portion is read from a first sector of one of the plurality of blocks, and a second portion is read from a second sector of one of the plurality of blocks, and wherein each first sector of each of the plurality of blocks is encrypted using a first encryption key, and each second sector of each of the plurality of blocks is encrypted using a second encryption key that is different from the first encryption key, and the security header, corresponding to the encrypted content data of the plurality of data files, is read from at least one header block of the plurality of blocks, wherein the at least one header block is different from each one of the blocks in which the content data of the plurality of data files is stored;
• decrypting the content data portions stored in each of the sectors by performing sector level decryption by using a first decryption key to decrypt data read from the first sector of each of the plurality of blocks and using a second decryption key that is different from the first decryption key to decrypt data read from the second sector of each of the plurality of blocks;
• and
• checking the integrity of the block permission table based on the integrity check value generated based on the memory identifier,
• wherein the security header read from the header block includes each encryption key used to encrypt each encrypted content data portion read from each of the plurality of blocks.