Many distance bounding protocols appropriate for the RFID technology have been proposed recently. Unfortunately, they are commonly designed without any formal approach, which leads to inaccurate analyzes and unfair comparisons. Motivated by this need, we introduce a unified framework that aims to improve analysis and design of distance bounding protocols. Our framework includes a thorough terminology about the frauds, adversary and prover, thus disambiguating many misleading terms. It also explores the adversary's capabilities and strategies, and addresses the impact of the prover's ability to tamper with his device. It thus introduces some new concepts in the distance bounding domain as the black-box and white-box models, and the relation between the frauds with respect to these models. The relevancy and impact of the framework is finally demonstrated on a study case: Munilla-Peinado distance bounding protocol.

Radio Frequency Identification (RFID) systems are vulnerable to relay attacks (i.e., mafia, terrorist and distance frauds) when they are used for authentication purposes. Distance bounding protocols are particularly designed as a countermeasure against these attacks. These protocols aim to ensure that the tags are in a distant area by measuring the round-trip delays during a rapid challenge-response exchange of short authenticated messages. Terrorist fraud is the most challenging attack to avoid, because a legitimate user (a tag owner) collaborates with an attacker to defeat the authentication system. Many RFID distance bounding protocols have been proposed recently, with encouraging results. However, none of them provides the ideal security against the terrorist fraud.Motivated by this need, we first introduce a strong adversary model for Physically Unclonable Functions (PUFs) based authentication protocol in which the adversary has access to volatile memory of the tag. We show that the security of Sadeghi et al.'s PUF based authentication protocol is not secure in this model. We provide a new technique to improve the security of their protocol. Namely, in our scheme, even if an adversary has access to volatile memory she cannot obtain all long term keys to clone the tag. Next, we propose a novel RFID distance bounding protocol based on PUFs which satisfies the expected security requirements. Comparing to the previous protocols, the use of PUFs in our protocol enhances the system in terms of security, privacy and tag computational overhead. We also prove that our extended protocol with a final signature provides the ideal security against all those frauds, remarkably the terrorist fraud. Besides that, our protocols enjoy the attractive properties of PUFs, which provide the most cost efficient and reliable means to fingerprint chips based on their physical properties.

The recent advent of ubiquitous technologies has raised an important concern for citizens: the need to protect their privacy. So far, this wish was not heard of industrials, but national and international regulation authorities, as the European Commission recently published some guidelines to enforce customers' privacy in RFID systems: "Privacy by design" is the way to be followed as stated in EC Recommendation of 12.5.2009. Research on privacy is an active domain but there is still a wide gap between theory and everyday life's applications. Filling this gap will require academia to design protocols and algorithms that fit the real-life constraints. In this paper, we provide a comprehensive analysis of privacy-friendly authentication protocols devoted to RFID that: 1) are based on well-established symmetric-key cryptographic building blocks; 2) require a reader complexity lower than OðNÞ where N is the number of provers in the system. These two properties are sine qua non conditions for deploying privacy-friendly authentication protocols in large-scale applications, for example, access control in mass transportation. We describe existing protocols fulfilling these requirements and point out their drawbacks and weaknesses. We especially introduce attacks on CHT, CTI,YA-TRAP*, and the variant of OSK/AO with mutual authentication. We also raise that some protocols, such as O-RAP, O-FRAP, and OSK/BF, are not resistant to timing attacks. Finally, we select some candidates that are, according to our criteria, the most appropriate ones for practical uses.

Distance-bounding protocols allow a verifier to both authenticate a prover and evaluate whether the latter is located in his vicinity. These protocols are of particular interest in contactless systems, e.g., electronic payment or access control systems, which are vulnerable to distance-based frauds. This survey analyzes and compares in a unified manner many existing distance-bounding protocols with respect to several key security and complexity features.

Private function evaluation (PFE) is a special case of secure multi-party computation (MPC), where the function to be computed is known by only one party. PFE is useful in several real-life settings where an algorithm or a function itself needs to remain secret due to its confidential classification or intellectual property. In this work, we look back at the seminal PFE framework presented by Mohassel and Sadeghian at Eurocrypt'13. We show how to adapt and utilize the wellknown half gates garbling technique (Zahur et al., Eurocrypt'15) to their constant round 2-party PFE scheme. Compared to their scheme, our resulting optimization considerably improves the efficiency of both the underlying Oblivious Evaluation of Extended Permutation (OEP) and secure 2-party computation (2PC) protocol, and yields a more than 40% reduction in overall communication cost (the computation time is also slightly decreased, and the number of rounds remains unchanged).

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Norway experienced internet voting in 2011 and 2013 for municipal and parliamentary elections, respectively. Its security depends on the assumptions that the involving organizations are completely independent, reliable, and the receipt codes are securely sent to the voters. In this paper, we point out the following aspects: The vote privacy of the Norwegian scheme is violated if Ballot Box and Receipt Generator cooperate because the private key of Decryption Service can be obtained by the two former players. We propose a solution to avoid this issue without adding new players. To assure the correctness, the receipt codes are sent to the voters over a pre‐channel (postal service) and a post‐channel (Short Message Service [SMS]). However, by holding both SMS and the postal receipt code, a voter can reveal his vote even after the elections. Albeit revoting is a fairly well solution for coercion or concealment, intentional vote revealing is still a problem. We suggest SMS only for notification of vote submission. In case the codes are falsely generated or the pre‐channel is not secure, a vote can be counted for a different candidate without detection. We propose a solution in which voters verify the integrity of the postal receipt codes. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper, we classify the RFID distance bounding protocols having bitwise fast phases and no final signature. We also give the theoretical security bounds for two specific classes, leaving the security bounds for the general case as an open problem. As for the classification, we introduce the notion of k-previous challenge dependent (k-PCD) protocols where each response bit depends on the current and k-previous challenges and there is no final signature. We treat the case k = 0, which means each response bit depends only on the current challenge, as a special case and define such protocols as current challenge dependent (CCD) protocols. In general, we construct a trade-off curve between the security levels of mafia and distance frauds by introducing two generic attack algorithms. This leads to the conclusion that CCD protocols cannot attain the ideal security against distance fraud, i.e. 1/2, for each challenge-response bit, without totally losing the security against mafia fraud. We extend the generic attacks to 1-PCD protocols and obtain a trade-off curve for 1-PCD protocols pointing out that 1-PCD protocols can provide better security than CCD protocols. Thereby, we propose a natural extension of a CCD protocol to a 1-PCD protocol in order to improve its security. As a study case, we give two natural extensions of Hancke and Kuhn protocol to show how to enhance the security against either mafia fraud or distance fraud without extra cost.