Tag privacy protection method, update solicitor, program therefor and record medium carrying such program in storage

摘要

An update solicitor apparatus (2620) for soliciting an updater to update privileged ID in a tag device (2610), which is provided externally of a he tag device, comprises: a privileged ID input section (2022) to which a plurality of kinds of privileged ID's, which are re-encryptable encrypted texts corresponding to an identical tag ID information, are input; a privileged ID memory (2625) for storing the plurality of kinds of privileged ID's which are input thereto; a privileged ID extractor (2624) connected to the privileged ID memory (2625) for extracting any one of the privileged ID's from the privileged ID memory (2625) at a given opportunity; and a privileged ID output section (2022) for delivering the extracted privileged ID to the tag device (2610) in order to update current privileged ID stored in the tag device (2610) with the extracted privileged ID. The current privileged ID differs from the extracted privileged ID, both the current privileged ID and the extracted privileged ID corresponding to the identical tag ID information.