| 摘要 |
<P>PROBLEM TO BE SOLVED: To inexpensively and sufficiently prevent the tracking of ID information by an unauthorized third party without applying a large processing load to a center device in RFID and AutoID or the like. <P>SOLUTION: Recording ID information UIDj and temporary information CNT<SB>k</SB>are recorded in a tag device 10. A master key and its key ID number (MKj, KIDj) are recorded in the tag device 10 and the center device 30. A temporary key OSK<SB>k</SB>is generated by using the CNT<SB>k</SB>and the MKj in the tag device 10. The UIDj is encrypted by using the temporary key OSK<SB>k</SB>, and variable ID information nonceID<SB>k</SB>is generated. After the temporary information CNT<SB>k</SB>is updated to CNT<SB>k+1</SB>in the tag device 10; the generated nonceID<SB>k</SB>, the CNT<SB>k</SB>, and the KIDj are transmitted to the center device 30. The center device 30 generates the OSK<SB>k</SB>by using the nonceID<SB>k</SB>, the CNT<SB>k</SB>, the KIDj, and the recorded (MKj, KIDj) and decrypts the UIDj. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
