Method for generating data for detection of tampering, and method and apparatus for detection of tampering

In a target apparatus which stores at least one piece of domain key information in a first area and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information in a second area different from the first area, a method for detecting tampering of one of the plurality of pieces of content key information, comprising:

• a first calculation step of subjecting the one of the plurality of pieces of content key information to a first calculation to obtain check data;
• a first comparison step of comparing the check data obtained in the first calculation step with check data previously stored in the second area;
• an extraction step of extracting a plurality of pieces of check data associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, without performing the first calculation, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation step of subjecting the plurality of pieces of check data extracted in the extraction step to a second calculation to obtain whole check data;
• and
• a second comparison step of comparing the whole check data obtained in the second calculation step with whole check data previously stored in the first area and associated with the same domain key information.

In a target apparatus which stores at least one piece of domain key information in an encrypted state and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information in an encrypted state, a method for detecting tampering of one of the plurality of pieces of content key information, wherein

• in the target apparatus, a whole check value encrypted using a chain encryption technique and a whole check value in plain text are previously stored,
• the method comprises:
• a first calculation step of subjecting the one piece of the plurality of pieces of content key information to a first calculation to obtain check data;
• a first comparison step of comparing the check data obtained in the first calculation step with check data previously stored in the target apparatus;
• an extraction step of extracting a plurality of pieces of check data in an encrypted state and associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation step of concatenating the plurality of pieces of check data in the encrypted state and the encrypted whole check value to obtain concatenated data, and decrypting the concatenated data to obtain the whole check value in plain text;
• and
• a second comparison step of comparing the whole check value in plain text obtained in the second calculation step with the whole check value in plain text previously stored.

In a target apparatus which stores at least one piece of domain key information and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information, a method for detecting tampering of one of the plurality of pieces of content key information, wherein

• each of the plurality of pieces of content key information is encrypted using a chain encryption technique and is stored in the target apparatus;
• the method comprises:
• a first calculation step of decrypting the one of the plurality of pieces of content key information and extracting data at a predetermined position to obtain a check value;
• a first comparison step of comparing the check value obtained in the first calculation step with a check value previously stored in the target apparatus;
• an extraction step of extracting a plurality of check values associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation step of subjecting the plurality of check values extracted in the extraction step to a second calculation to obtain whole check data;
• and
• a second comparison step of comparing the whole check data obtained in the second calculation step with whole check data previously stored and associated with the same domain key information.

In a target apparatus which stores at least one piece of domain key information in a first area and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information in a second area different from the first area, an apparatus for detecting tampering of one of the plurality of pieces of content key information, comprising:

• a first calculation section of subjecting the one of the plurality of pieces of content key information to a first calculation to obtain check data;
• a first comparison section of comparing the check data obtained in the first calculation section with check data previously stored in the second area;
• an extraction section of extracting a plurality of pieces of check data associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, without performing the first calculation, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation section of subjecting the plurality of pieces of check data extracted in the extraction section to a second calculation to obtain whole check data;
• and
• a second comparison section of comparing the whole check data obtained in the second calculation section with whole check data previously stored in the first area and associated with the same domain key information.

In a target apparatus which stores at least one piece of domain key information in an encrypted state and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information in an encrypted state, an apparatus for detecting tampering of one of the plurality of pieces of content key information, wherein

• in the target apparatus, a whole check value encrypted using a chain encryption technique and a whole check value in plain text are previously stored,
• the apparatus comprises:
• a first calculation section of subjecting the one piece of the plurality of pieces of content key information to a first calculation to obtain check data;
• a first comparison section of comparing the check data obtained in the first calculation section with check data previously stored in the target apparatus;
• an extraction section of extracting a plurality of pieces of check data in an encrypted state and associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation section of concatenating the plurality of pieces of check data in the encrypted state and the encrypted whole check value to obtain concatenated data, and decrypting the concatenated data to obtain the whole check value in plain text;
• and
• a second comparison section of comparing the whole check value in plain text obtained in the second calculation step with the whole check value in plain text previously stored.

In a target apparatus which stores at least one piece of domain key information and a plurality of pieces of content key information each associated with any one of the at least one piece of domain key information, an apparatus for detecting tampering of one of the plurality of pieces of content key information, wherein

• each of the plurality of pieces of content key information is encrypted using a chain encryption technique and is stored in the target apparatus;
• the apparatus comprises:
• a first calculation section of decrypting the one of the plurality of pieces of content key information and extracting data at a predetermined position to obtain a check value;
• a first comparison section of comparing the check value obtained in the first calculation section with a check value previously stored in the target apparatus;
• an extraction section of extracting a plurality of check values associated with the plurality of pieces of content key information associated with one of the at least one piece of domain key information, wherein the one of the at least one piece of domain key information is the same domain key information as that associated with the one of the plurality of pieces of content key information;
• a second calculation section of subjecting the plurality of check values extracted in the extraction section to a second calculation to obtain whole check data;
• and
• a second comparison section of comparing the whole check data obtained in the second calculation section with whole check data previously stored and associated with the same domain key information.