摘要:Two effective attacks, namely de-synchronization attack and impersonation attack, against Ha et al.’s LCSS RFID authentication protocol, Song and Mitchell’s protocol are identified. The former attack can break the synchronization between the RFID reader and the tag in a single protocol run so that they can not authenticate each other in any following protocol run. The latter can impersonate a legal tag to spoof the RFID reader by extracting the ID of a specific tag during the authentication process. An impersonation attack against Chen et al.’s RFID authentication scheme is also identified. By sending malicious queries to the tag and collecting the response messages emitted by the tag, the attack allows an adversary to extract the secret information from the tag and further to impersonate the legal tag.