Panasonic Corporation

Kazuya Shimizu

Makoto Fujiwara

Shinji Inoue

Makoto Ochi

Yuishi Torisaki

Yusuke Nemoto

Kazuya Fujimura

Tomoya Sato

Kentaro Shiomi

Tomoya Satou

Kentarou Shiomi

In the case where a target device stores: m keys {Ka, . . . , Kam} (m is a natural number) in a manner that the Kai (i is a natural number satisfying 1&#x2266;i&#x2266;m) is encrypted with the Ka (i&#x2212;1); and n keys {Kb, . . . , Kbn} (n is a natural number) in a manner that the Kbj (j is a natural number satisfying 1&#x2266;j&#x2266;n) is encrypted with the Kb (j&#x2212;1), a confidential information processing unit is caused to perform a processing of re-encrypting the encrypted key Enc (Kai, Ka (i&#x2212;1)), which has been encrypted with the Ka (i&#x2212;1), by using the Kb (j&#x2212;1) and outputting as an encrypted key Enc (Kai, Kb (j&#x2212;1)).

Confidential information processing host device and confidential information processing method

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 domain key information in a second area, a method for generating data for detecting tampering of the content key information. The method comprises the steps of encrypting the content key information associated with one of the domain key information using a chain encryption technique, extracting data at predetermined positions in the encrypted content key information, concatenating the pieces of data extracted at the predetermined positions in the encrypted content key information to obtain concatenated data, performing a hash calculation with respect to the concatenated data to obtain a hash value, storing check values corresponding to the data at the predetermined positions in plain text, in the target apparatus, and storing the hash value in the target apparatus.

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

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Osaka, Japan

Kazuya Shimizu