Security Analysis of a Privacy-preserving ECC-based Grouping-proof Protocol

Batina et al. have proposed a privacy-preserving grouping-proof RFID protocol with colluding tag prevention (CTP) recently which relies exclusively on the use of Elliptic Curve Cryptography (ECC). In this paper, we show that this proposed protocol is not secure against the tracking attack. To make this attack successfully, the adversary needs to execute three phases. Firstly, the attacker just eavesdrops on the messages exchanged between Reader and Tags. Secondly, the attacker impersonates Reader to replay the message which is got from the first phase. Finally, the adversary acts as a man in the middle to tamper the messages exchanged between Reader and Tag B. Then we propose an enhancement and prove that the revision is secure against the tracking attack which keeps other security properties.