3.2 Assumption

The following assumptions are made regarding the system:

• The open nature of the wireless communication between smart tags and RFID readers enables outside attackers to monitor the communication.
• Smart tags can be stolen, and then attackers can use the stolen tags to impersonate legitimate identity to access resources.
• RFID readers can also be stolen, and the attackers can use the stolen reader to impersonate some other innocent (uncompromised) smart tags.
• The trusted third-party authority is always trustworthy and will not deviate from its normal operations.
• Each smart tag has a rewritable memory, and is computationally powerful to perform a light-weight cryptographic function, such as SHA-1.