METHOD, DEVICE, AND PROGRAM FOR DECODING, AND TERMINAL DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce calculation load in decoding process of a content file equipped with a right object file containing a content key for an encrypted content file.

SOLUTION: A right object is parsed in advance and a content key is taken out. The content key is re-encrypted using a key encryption key which is a secret key specific to a terminal, and is stored in a security memory. When reproducing a content file, the content key having been re-encrypted is read out of the security memory. The key encryption key is used for decoding, and the content file is decoded and reproduced by using the decoded content key. The right object with a high calculation load can be parsed before reproducing the content. So the parsing process can be omitted at reproduction of the content, reducing significantly the calculation load before decoding when the content file is reproduced.

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