Abstract: There has been no method for authenticity assessment which can be performed by ordinary people using an identification mark which absolutely cannot be duplicated. A minute mark is printed on a medium as an identification mark. An image of the identification mark having a minute shape which is formed by fixing a printing substance and which cannot be artificially controlled are memorized, and the image are stored together a serial number of the article as a master image. The article is placed on the market together with a warranty card including the identification mark. An ordinary person gets access to the webpage of an authenticity assessment management center, transmits the serial number of the target article, magnifies the identification mark on the warranty card by a microscope, captures an image of the identification mark with a camera-equipped cell-phone, and then transmits the image to the authenticity assessment management center.