Patent ID: 7373506

Claim:
A data processing apparatus for processing content data provided by a recording or communication medium, said apparatus comprising: a cryptography process section for executing a cryptography process on said content data; and a control section for executing control for said cryptography process section, wherein said cryptography process section is configured to: split a first portion of header data of the content data having data on usage policy into a plurality of first messages, said header data including a first stored check value therein, generate a first integrity check value or values from a first key stored in said cryptography process section to verify integrity of the header data by using said plurality of first messages, collate said first integrity check value or values to verify said first portion of the header data including the usage policy by comparing said first integrity check value or values to said first stored check value, split a second portion of the header data of the content data having a content key into a plurality of second messages, said header data including a second stored check value therein, generate a second integrity check value or values from a second key stored in said cryptography process section to verify integrity of the header data by using said plurality of second messages, wherein said second integrity check value or values is generated by applying the second key to a block information table key, the content key and a block information table, collate said second integrity check value or values to verify said second portion of the header data including said block information table by comparing said second integrity check value or values to said second stored check value, generate an intermediate integrity check value based on said first integrity check value or values and said second integrity check value or values, and use said intermediate integrity check value to verify said content data corresponding to said first and second integrity check values.