| US 7,549,061 B2 | ||
| Unauthorized contents detection system | ||
| Masao Nonaka, Osaka (Japan); Yuichi Futa, Osaka (Japan); Toshihisa Nakano, Osaka (Japan); Kaoru Yokota, Hyogo (Japan); Motoji Ohmori, Osaka (Japan); Masaya Miyazaki, Osaka (Japan); Masaya Yamamoto, Osaka (Japan); Kaoru Murase, Nara (Japan); and Senichi Onoda, Osaka (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Appl. No. 10/593,561 PCT Filed Mar. 24, 2005, PCT No. PCT/JP2005/006215 § 371(c)(1), (2), (4) Date Sep. 20, 2006, PCT Pub. No. WO2005/096119, PCT Pub. Date Oct. 13, 2005. |
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| Claims priority of application No. 2004-110069 (JP), filed on Apr. 02, 2004; application No. 2004-146963 (JP), filed on May 17, 2004; application No. 2004-151621 (JP), filed on May 21, 2004; application No. 2004-163734 (JP), filed on Jun. 01, 2004; application No. 2004-196531 (JP), filed on Jul. 02, 2004; application No. 2004-201009 (JP), filed on Jul. 07, 2004; and application No. 2004-206335 (JP), filed on Jul. 13, 2004. | ||
| Prior Publication US 2007/0198838 A1, Aug. 23, 2007 | ||
| Int. Cl. H04L 9/00 (2006.01); H04K 1/00 (2006.01); G06F 11/30 (2006.01); G06F 12/14 (2006.01); H04L 9/32 (2006.01); G06F 17/00 (2006.01) | ||
| U.S. Cl. 713—193 [713/179; 713/180; 713/181; 380/251; 380/259; 707/100; 707/101] | 11 Claims |
| 1. A data processing device for playing back a digital work recorded on a recording medium having also recorded thereon (i)
a plurality of record digest values generated from a plurality of data blocks constituting the digital work and (ii) record
signature data generated by applying, with use of a signature key, a signature generating algorithm to a first combination
made of some or all of the plurality of record digest values, the data processing device comprising:
a verification key storing unit configured to store a verification key corresponding to the signature key;
a using unit configured to play back the digital work;
a selecting unit configured to, each time the digital work is played back, randomly select a predetermined number of data
blocks from all of the plurality of data blocks, the predetermined number being smaller than the number of all the plurality
of data blocks;
a calculating unit configured to calculate a plurality of calculation digest values from the selected data blocks;
a reading unit configured to read remaining record digest values corresponding to unselected data blocks from among the plurality
of record digest values;
a generating unit configured to generate a second combination based on calculation digest values and the remaining record
digest values, the second combination being the same as data which is generated from the first combination by replacing record
digest values corresponding to the selected data blocks with corresponding calculation digest values;
a signature verifying unit configured to verify the record signature data by applying, with use of the verification key, a
signature verification algorithm to the second combination and the record signature data; and
a use controlling unit configured to stop said using unit from playing back the digital work when the verification is unsuccessful.
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