Image file distribution apparatus, image file recovery apparatus, image file distribution method, image file recovery method, image file distribution program, image file recovery program, and recording medium storing program

Abstract

Provided are an image file distribution apparatus, an image file recovery apparatus, an image file distribution method, an image file recovery method, an image file distribution program, an image file recovery program, and a recording medium storing the program which can prevent a relatively large increase in the amount of data of an image file even when an (k, n) secret sharing scheme with high security is used. For example, distributed tag information is obtained from tag information of the image file by a (k, n)-threshold secret sharing scheme. For example, distributed image data is obtained from image data by a (k, L, n)-threshold ramp secret sharing scheme. For example, the distributed tag information and the distributed image data are combined to obtain combined data. Since the amount of data in the tag information is small, the use of the (k, n) secret sharing scheme does not cause a large increase in the amount of data. Since the (k, L, n)-threshold ramp secret sharing scheme does not cause a large increase in the amount of data, an increase in the total amount of data in the image data is relatively small.