| 摘要 |
PROBLEM TO BE SOLVED: To provide an encryption/decryption system and method which can update boundary information in encryption even after an encryption file is created, makes it difficult to specify a used encryption algorithm in decryption, and can ensure safety by increasing resistance to analysis of the encryption file. SOLUTION: Plain text data is segmented into multiple data at the encryption function section 3 of an encryption section 1 according to a region segmentation strategy. Each plain text data thus segmented is then encrypted by a different encryption algorithm, and then the segment position and the used encryption algorithm are associated with each other and held as boundary information. A decryption algorithm, a boundary zone and an encryption data are coupled loosely. A self decryption function section 5 of a decryption section 2 first takes out the boundary information from a boundary zone 33, inspects a self decryption type encryption file 34 by using that boundary information, and decrypts encryption data 31 when the file 34 passes the inspection. COPYRIGHT: (C)2009,JPO&INPIT
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