Tag privacy protection method, tag device, back-end device, update device, update request device, program thereof, and recording medium storing these programs

摘要

In the first invention, in response to the call from the reader device, the tag device reads the secret value from the secret value memory in the second arithmetic unit, and disturbs the relationship between the domain element and its mapping. The tag output information obtained by applying the function F2 is generated. This tag output information is sent to the output unit, from which it is output to the back-end device. Thereafter, in the first arithmetic unit, at least a part of the secret value is read from the secret value memory, and the first function F1 for which it is difficult to obtain an inverse image is applied to the element. Overwrite and update the secret value in In the second invention, in the updating device provided outside the tag device, the concealment ID information stored in the tag device is a new concealment ID that is difficult to grasp the relevance of the information with a predetermined opportunity. Update to information.