关键词: RFID标签, 更新过程, 不可链接性

Abstract: Based on the analysis of previous security strategy about RFID tags，this paper proposes a kind of new security strategy built on random update process which can solve the security problems effectively occurred in the RFID tags，and does not required much computational power and cryptographic techniques.The strategy can change the tag data at random driven by the internal circuitry during each activation and informs the change to the system.Then the system may modify the appropriate entry in its database.After a certain number of activations the new tag data cannot be linked with the original one so as to avoid illegal tracing.Besides，the definition of unlinkability is given，and the detail analysis is provided based on relative theories.

Key words: RFID tags, update process, unlinkability