ENCIPHERING AND DECODING METHOD FOR PICTURE FILE AND ENCIPHERING AND DECODING DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an enciphering, decoding method and an enciphering and decoding device for a picture file which can attain enciphering with regard to a versatile file format. SOLUTION: With regard to a standard JPEG file 2 which can be obtained by compression processing an original picture 1 at a compression processing part 7, an enciphered JPEG file 5 is obtained by a marker operation processing part 5 performing a specified operation processing with a specific marker in accordance with a marker operation rule. The enciphered JPEG file 5 is returned to the standard JPEG file 2 by a marker reverse operation processing part 6 recovering the specific marker operation processing in accordance with the marker operation rule. After that, a recovery picture 3 can be obtained by being extension processed by an extension processing part 8.