IMAGE ENCRYPTION APPARATUS, IMAGE DECRYPTION APPARATUS, IMAGE ENCRYPTION METHOD, IMAGE DECRYPTION METHOD, AND IMAGE ENCRYPTION PROGRAM

摘要

PROBLEM TO BE SOLVED: To maintain sufficient security in information management while achieving authority management in decryption within encryption areas.

SOLUTION: The designation of a part to be encrypted in image data 10 is received and encryption areas (areas surrounded by dotted lines) are set. For the encryption areas, the designation of an authority level is received. Upon being triggered by an input password or the like, an encryption key is generated for each received authority level. Decryption confirmation information (L-shaped parts at four corners of the encryption area) for verifying whether or not the encryption area is appropriately decrypted through decryption is implanted in the encryption area. Image encryption is performed on the encryption area where the decryption confirmation information is implanted, by using the encryption key corresponding to the authority level designated for the encryption area. In decryption, all decryption keys corresponding to all authority levels lower than or equal to the set authority level are used to decrypt each encryption area and whether or not appropriate decryption has been performed is determined on the basis of the result of the detection of the decryption confirmation information.

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