Abstract. RFID-based tokens are increasingly used in electronic payment and ticketing systems for mutual authentication of tickets and terminals. These systems typically use cost-effective tokens without expensive hardware protection mechanisms and are exposed to hardware attacks that copy and maliciously modify tokens. Physically Unclonable Functions (PUFs) are a promising technology to protect against such attacks by binding security critical data to the physical characteristics of the underlying hardware. However, existing PUF-based authentication schemes for RFID do not support mutual authentication, are often vulnerable to emulation and denial-of service attacks, and allow only for a limited number of authentications. In this paper, we present a new PUF-based authentication scheme that overcomes these drawbacks: it supports PUF-based mutual authentication between tokens and readers, is resistant to emulation attacks, and supports an unlimited number of authentications without requiring the reader to store a large number of PUF challenge/response pairs. In this context, we introduce reverse fuzzy extractors, a new approach to correct noise in PUF responses that allows for extremely lightweight implementations on the token. Our proof-of-concept implementation shows that our scheme is suitable for resource-constrained devices.

Abstract. Physically unclonable functions (PUFs) exploit the unavoidable manufacturing variations of an integrated circuit (IC). Their input-output behavior serves as a unique IC 'fingerprint'. Therefore, they have been envisioned as an IC authentication mechanism, in particular the subclass of so-called strong PUFs. The protocol proposals are typically accompanied with two PUF promises: lightweight and an increased resistance against physical attacks. In this work, we review nineteen proposals in chronological order: from the original strong PUF proposal (2001) to the more complicated noise bifurcation and system of PUF proposals (2014). The assessment is aided by a unified notation and a transparent framework of PUF protocol requirements.

We propose a new distance bounding protocol, which builds upon the private RFID authentication protocol by Peeters and Hermans [25]. In contrast to most distance-bounding protocols in literature, our construction is based on publickey cryptography. Public-key cryptography (specifically Elliptic Curve Cryptography) can, contrary to popular belief, be realized on resource constrained devices such as RFID tags. Our protocol is wide-forward-insider private, achieves distance-fraud resistance and near-optimal mafia-fraud resistance. Furthermore, it provides strong impersonation security even when the number of time-critical rounds supported by the tag is very small. The computational effort for the protocol is only four scalar-EC point multiplications. Hence the required circuit area is minimal because only an ECC coprocessor is needed: no additional cryptographic primitives need to be implemented.