Information processing apparatus, information processing method, and program storage medium

An information processing apparatus comprising:

• a memory configured to store content data;
• a setting unit configured to set a sequential number corresponding to the content data, the sequential number incremented by one when an operation is performed on the content data stored in the memory;
• a calculation unit configured to calculate a hash value corresponding to the content data by performing a predetermined calculation using at least a part of the management data associated with the content data and the sequential number;
• a comparison unit configured to compare a stored hash value included in a header of the content data with the hash value of the content data calculated by the calculation unit upon receiving a request to perform an operation on the content data;
• and
• a control unit configured to control reproduction of the content data based on the result of the comparison performed by the comparison unit.

An information processing apparatus comprising:

• means for storing content, said content comprising management information and calculation information;
• means for storing a sequential number incremented upon each operation on the content stored in content storage, the sequential number associated with the content stored in the content storage;
• means for calculating the calculation information based on the management information and a latest sequential number stored in the memory;
• means for incrementing the sequential number upon receiving a request to perform an operation on the content and storing the incremented sequential number in the means for storing a sequential number;
• means for updating the management information upon receiving a request to perform an operation on the content, and storing the updated management information in the means for storing content;
• means for reading the calculation information included in the content from the means for storing content, the management information included in the content, and the latest sequential number from the means for storing a sequential number;
• means for comparing calculation information included in the content read by the reading means with calculation information calculated by the calculation means upon receiving a request to perform an operation on the content;
• and
• means for controlling an operation on the content based on a result of the comparison done by the means for comparing.

An information processing method, comprising the steps of:

• storing content in a first memory, said content comprising management information and calculation information;
• storing a sequential number incremented upon each operation on the content stored in a second memory, the sequential number associated with the content stored in the first memory;
• calculating the calculation information based on the management information and a latest sequential number stored in the second memory;
• incrementing the sequential number upon receiving a request to perform an operation on the content and storing the incremented sequential number in the second memory;
• updating the management information upon receiving a request to perform an operation on the content, and storing the updated management information in the first memory;
• reading the calculation information included in the content from the first memory, the management information included in the content, and the latest sequential number from the second memory;
• comparing calculation information included in the content read in the reading step with calculation information calculated in the calculating step upon receiving a request to perform an operation on the content;
• and
• controlling an operation on the content based on a result of the comparing step.

An information processing apparatus comprising:

• a content memory configured to store content comprising management information and calculation information;
• a memory configured to store a sequential number incremented upon each operation on the content stored in the content memory, the sequential number associated with the content stored in the content memory;
• a processor configured to calculate the calculation information based on the management information and a latest sequential number stored in the memory;
• the processor configured to increment the sequential number upon receiving a request to perform an operation on the content and storing the incremented sequential number in the memory;
• the processor configured to update the management information upon receiving a request to perform an operation on the content, and storing the updated management information in the content memory;
• the processor configured to read the calculation information included in the content from the content memory, the management information included in the content, and the latest sequential number from the memory;
• the processor configured to compare calculation information included in the content read by the processor with calculation information calculated by the processor upon receiving a request to perform an operation on the content;
• and
• a controller configured to control an operation on the content based on a result of the comparison performed by the processor.