• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.5
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• pp.99-109
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• 2007

Lee et al. recently proposed an RFID mutual authentication scheme based on synchronized secret information. However, we found that their protocol is vulnerable to a spoofing attack in which an adversary can impersonate a legal tag to the reader by sending a malicious random number. To remedy this vulnerability, we propose two RFID authentication protocols which are secure against all possible threats including backward and forward traceability. Furthermore, one of the two proposed protocols requires only three hash operations(but, $[m/2]{\cdot}2+3$ operations in resynchronization state, m is the number of tags) in the database to authenticate a tag, hence it is well suitable fur large scale RFID systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.73-90
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• 2010

Recently, Tan et al. introduced a serverless search protocol in which a mobile reader maintains a tag authentication list and authenticates a tag using the list without connecting authentication server. A serverless RFID system is different from general RFID systems which use on-line server models. In the serverless RFID system, since the mobility of a personalized reader must be considered, we have to protect not only the privacy of a tag but also the privacy of a mobile reader. In this paper, we define new security requirements for serverless RFID search system and propose a secure serverless RFID search system. In our system, since tag authentication information maintained by a reader is updated in every session, we can provide the backward untraceability of a mobile reader. Also we use an encrypted timestamp to block a replay attack which is major weakness of search protocols. In addition, we define a new adversary model to analyze a serverless RFID search system and prove the security of our proposed system using the model.