Time-of-flight distance-bounding protocols are potentially useful in RFID and NFC environments and are designed to discourage a number of attacks that take advantage of the inherent assumption that a token and reader that manages to communicate are located in close physical proximity to each other. These protocols are dependent on time measurements made at the physical layer of the communication channel, and thus require special high bandwidth channels with low latency. Executing a distance-bound protocol on a suitable channel in a constrained environment would potentially allow for bit errors during communication. Currently, terrorist fraud is discouraged in distance-bounding protocols by ensuring that a prover collaborating with an the attacker in this fraud has to make his secret key known to the attacker. We discuss the effect of making a protocol resistant to bit errors and show that the approach to design protocols against terrorist fraud is significantly weakened by error resistance, as a prover is potentially able to keep his key secret or hinder an attacker from learning his key.
Time-of-flight distance-bounding protocols are potentially useful in RFID and NFC environments and are designed to discourage a number of attacks that take advantage of the inherent assumption that a token and reader that manages to communicate are located in close physical proximity to each other. These protocols are dependent on time measurements made at the physical layer of the communication channel, and thus require special high bandwidth channels with low latency. Executing a distance-bound protocol on a suitable channel in a constrained environment would potentially allow for bit errors during communication. Currently, terrorist fraud is discouraged in distance-bounding protocols by ensuring that a prover collaborating with an the attacker in this fraud has to make his secret key known to the attacker. We discuss the effect of making a protocol resistant to bit errors and show that the approach to design protocols against terrorist fraud is significantly weakened by error resistance, as a prover is potentially able to keep his key secret or hinder an attacker from learning his key.
We consider the problem of distance bounding verification (DBV), where a proving party claims a distance and a verifying party ensures that the prover is within the claimed distance. Current approaches to "secure" distance estimation use signal's time of flight, which requires the verifier to have an accurate clock. We study secure DBV using physical channel properties as an alternative to time measurement. We consider a signal propagation environment that attenuates signal as a function of distance, and then corrupts it by an additive noise. We consider three attacking scenarios against DBV, namely distance fraud (DFA), mafia fraud (MFA) and terrorist fraud (TFA) attacks. We show it is possible to construct efficient DBV protocols with DFA and MFA security, even against an unbounded adversary; on the other hand, it is impossible to design TFA-secure protocols without time measurement, even with a computationally-bounded adversary. We however provide a TFA-secure construction under the condition that the adversary's communication capability is limited to the bounded retrieval model (BRM). We use numerical analysis to examine the communication complexity of the introduced DBV protocols. We discuss our results and give directions for future research.
Distance-bounding (DB) protocols let a verifier upper-bound a prover's physical distance by timing rapid challenge-response exchanges. Quantum communication promises simpler DB protocols with stronger security guarantees, yet existing quantum distance-bounding (QDB) proposals are analysed in ad-hoc models and, to the best of our knowledge, lack a common game-based treatment of standard fraud attacks. We contribute (i) a reusable security framework for QDB that fixes system and timing assumptions, specifies a quantum-capable adversary model, formalises distance-, mafia-, and terrorist-fraud experiments, and includes a simple i.i.d. depolarizing noise model; and (ii) an application of this framework to a published QDB protocol. For this protocol we characterise the honest per-round acceptance probability under noise and lift it to the multi-round setting, yielding explicit completeness guarantees as a function of the number of fast rounds, the acceptance threshold, and the noise parameter. For active adversaries we bound the per-round success probability of distance-fraud attacks and analyse the best known mafia-fraud strategy, deriving corresponding multi-round soundness bounds. We also show that the protocol is inherently insecure against terrorist-fraud in our model. The framework cleanly separates protocol-independent definitions from protocol-specific analysis and can be used to evaluate existing and future QDB protocols on a common basis.
Location (or distance) information of a device plays a significant role in current location-based systems. How to determine the location of a device or verify the location claims made by a device is challenging, as devices are untrusted and may have an incentive to claim a false location. In secure localization and positioning system, the trusted verifier(s) interact with the untrusted prover to determine its location or validate its location claim. In this thesis, we mainly focus on one of the prominent areas of such systems: distance bounding. Distance (upper) bounding (DUB) allows a verifier to verify whether a proving party is located within a certain distance bound. DUB protocols have many applications in secure authentication and location-based services. This thesis has two main contributions. The first is that we consider the dual problem of distance lower bounding (DLB), where the prover proves it is outside a distance bound from the verifier. We motivate this problem through a number of application scenarios and model security against distance fraud (DF), Man-in-the-Middle (MiM), and collusion fraud (CF) attacks. We prove impossibility of security against these attacks without making physical assumptions. We propose approaches to the construction of secure protocols under reasonable physical assumptions and give detailed design of a DLB protocol with security analysis using our proposed model. This is the first treatment of the DLB problem in the untrusted prover setting with a number of applications, raising new research directions and opportunities in location based services. We discuss our results and propose directions for future research. One of the main assumptions which DUB protocols rely on is that the time that the prover spends in receiving the challenge, processing, and sending the response is negligible compared to the propagation time of the signal between the prover and verifier. This strict requirement poses difficulties on the implementation of DUB protocols and limits the possible development of applications for distance bounding as well. The second contribution in this thesis is that we design a novel one-round DUB protocol that uses one-way transmission time to estimate the distance instead of round-trip time, so that the assumption of negligible processing time is not required any longer. In order to prove the security, we formalize the notion of time in a distributed environment with adversarial users. In this model, time is implemented by a trusted party broadcasting unpredictable timestamps at a high frequency. We show that the timestamp is proved to be fresh and unpredictable. We then extend the time model to formalize DUB protocols and define corresponding attacks. Finally, we prove the security of our proposed distance bounding protocol and discuss potential issues when implementing such protocol. Besides these two main contributions, we also have the following two contributions: (1) we identify and analyze a new attack: false rejection attack, which poses serious threat to proximity-based authentications that uses distance bounding protocol for proximity evaluation; (2) We investigate the feasibility of replay attack in context-based proximity authentication using real-world data.
Distance bounding protocols are launched based upon the round trip time measurements of the carried out messages to defend RFID systems against the relay attack. In such protocols, the reader authenticates tags and also estimates an upper bound for the physical distance between the tag and itself. Distance bounding protocols are vulnerable to mafia fraud and distance fraud attacks. In this paper, a new distance bounding protocol is proposed based on mutual utilization of binary predefined and random challenges. Moreover, this protocol is analyzed to compute the attacker's success probability due to mafia fraud and distance fraud attacks. In this case, the analysis and simulation results show that the proposed protocol obtains the desirable attackers' success probabilities, with minimum system memory requirement and minimum number of rounds compared with other distance bounding protocols employed by RFID systems.
RFID (radio frequency identification) systems, recently being used in a wide range of areas, are vulnerable to relay attack from malicious attackers. For that reason, Brands, et al. proposed a certification protocol between a certifier and a verifier based on the concept of distance-bounding, and in addition Hancke et al. introduced the concept of RFID. However, the delivery of tag IDs, one of the main RFID features, is not still available, and there are two important demerits: anonymity in the delivery of tag IDs suggested by Kim et al. and inefficiency in finding a tag ID with regard to how to check errors which may occur in the process of data exchange between readers and tags. Therefore, this study proposes a protocol that meets the requirements of tag anonymity and location untraceability, has resistance to errors which may take place in the phase of tag data exchange, and is very efficient in finding tag IDs.
Quantum distance-bounding (QDB) protocols let a verifier check that a prover is both genuine and physically nearby. During a timed fast phase of quantum communication, the verifier measures round-trip times to obtain an upper bound on the prover's distance. For a uniform comparison, we isolate the fast phase and study one-round distance-fraud (DF) and mafia-fraud (MF) games. For discrete-variable QDB, we show that these games reduce to convex optimization problems and can therefore be solved exactly with semidefinite programming; each MF value comes with an explicit attack achieving it and a matching certificate that no attack does better. This contrasts with quantum position verification, where an attack is split between two separated parties, so its optimization is nonconvex and analyses rely on relaxations. In our MF game, the cooperating pair collapses to a single sequential strategy, which keeps the game convex and its exact value computable. Across the discrete-variable protocols we examine, the best one-round DF attack succeeds with the same probability (1/2) for every protocol, whereas MF clearly separates the protocols. For continuous-variable QDB, we report estimated attack success probabilities from a calibrated Gaussian attack model. The benchmark covers protocols whose fast phase itself authenticates the prover; designs that follow Brands and Chaum and instead bind the fast phase with a final authenticated message, like the earliest QDB proposal, fall outside it and are treated separately. Of the four protocols studied, two had no previously known one-round attack values, and we report the first ones; for the other two, we find MF attacks with higher success probability than previously reported. Overall, one-round MF resistance depends on whether an attacker can use information revealed early by the prover to answer a fresh challenge from the verifier.