Abstract-RFID (Radio Frequency IDentification) tags need to include security functions, yet at the same time their resources are extremely limited. Moreover, to provide privacy, authentication and protection against tracking of RFID tags without loosing the system scalability, a public-key based approach is inevitable. In this paper, we present an architecture of a state-of-the-art processor for RFID tags with an Elliptic Curve (EC) processor over GF(2 163 ). It shows the plausibility of meeting both security and efficiency requirements even in a passive RFID tag. The proposed processor is able to perform EC scalar multiplications as well as general modular arithmetic (additions and multiplications) which are needed for the cryptographic protocols. As we work with large numbers, the register file is the most critical component in the architecture. By combining several techniques, we are able to reduce the number of registers from 9 to 6 in the EC processor. To obtain an efficient modulo arithmetic, we introduce a redundant modular operation. Moreover, the proposed architecture can support multiple cryptographic protocols. The synthesis results with a 0.13 µm CMOS technology show that the gate area of the most compact version is 12.5 Kgates.

Abstract-Operational and security requirements for RFID systems such as system scalability, anonymity and anti-cloning are difficult to obtain due to constraints in area, memory, etc. Due to scarceness of resources most of the proposed protocols were designed using symmetric key cryptographic algorithms. However, it has been shown that it is inevitable to use public-key cryptographic algorithms to satisfy these requirements [1]. Moreover, general public-key cryptography based authentication protocols are vulnerable in terms of anonymity, which is shown in this paper. Accordingly, we design a new authentication protocol named EC-RAC using EC (Elliptic Curve) cryptography. EC-RAC can be proved for its security in the generic group model and is carefully designed to minimize its computational workload. Moreover, we present the implementation results of EC-RAC to show its feasibility for RFID systems.

The emergence of pervasive computing devices has raised several privacy issues. In this paper, we address the risk of tracking attacks in RFID networks. Our contribution is threefold: (1) We repair three revised EC-RAC protocols of Lee, Batina and Verbauwhede and show that two of the improved authentication protocols are wide-strong privacypreserving and one wide-weak privacy-preserving; (2) We present the search protocol, a novel scheme which allows for privately querying a particular tag, and proof its security properties; and (3) We design a hardware architecture to demonstrate the implementation feasibility of our proposed solutions for a passive RFID tag. Due to the specific design of our authentication protocols, they can be realized with an area significantly smaller than other RFID schemes proposed in the literature, while still achieving the required security and privacy properties.

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