| 摘要 |
PROBLEM TO BE SOLVED: To block illegal utilization while minimizing a load of performing encryption processing on encoded data. SOLUTION: A portion to perform encryption processing thereon is extracted from coded image data 501 (coded data) by an encryption portion extraction unit, and partial data 561 are generated. An encryption processing unit performs encryption processing on the partial data 561 and processed partial data are generated. In the coded image data 501, the same portion as the portion from which the partial data 561 are extracted by the encryption portion extraction unit, is replaced with the processed partial data by a replacement unit. Extraction portions 541-550 to be extracted by the encryption portion extraction unit are defined in such a way that the rate of the extraction portions becomes higher as it gets closer to a head of the coded image data 501, and the rate of the extraction portions becomes lower as it gets far away from the head. COPYRIGHT: (C)2008,JPO&INPIT
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