Distance-bounding protocols provide strong security guarantees, yet their secure realization depends on high-precision physical-layer timestamping of signal transmission and reception. In principle, modern commodity IEEE 802.11 chipsets fulfill these technical requirements. However, distance-bounding research and experimentation on Wi-Fi remain severely limited, as the required high-precision timestamping functionality on 802.11 hardware is tightly coupled to fixed protocol exchanges (e.g., FTM) implemented in closed-source firmware. This restricts the freedom of open research.

Bluetooth provides encryption, authentication, and integrity protection of its connections. These protection mechanisms require that Bluetooth devices initially establish trust on first use through a process called pairing. Throughout this process, multiple alternative pairing methods are supported.In this paper, we describe a design flaw in the pairing mechanism of Bluetooth. This flaw permits two devices to perform pairing using differing methods. While successfully interacting with each other, the devices are not aware of the Method Confusion. We explain how an attacker can cause and abuse this Method Confusion to mount a Method Confusion Attack. In contrast to other attacks targeting the pairing method, our attack applies even in Bluetooth’s highest security mode and cannot be mitigated in the protocol. Through the Method Confusion Attack, an adversary can infiltrate the secured connection between the victims and intercept all traffic.Our attack is successful in practically relevant scenarios. We implemented it as an end-to-end Proof of Concept for Bluetooth Low Energy and tested it with off-the-shelf smartphones, a smartwatch and a banking device. Furthermore, we performed a user study where none of the 40 participants noticed the ongoing attack, and 37 (92.5%) of the users completed the pairing process. Finally, we propose changes to the Bluetooth specification that immunize it against our attack.

Many applications require positioning. Time of Flight (ToF) methods calculate distances by measuring the propagation time of signals. We present a novel ToF localization method. Our new approach works infrastructure-less, without pre-defined roles like Anchors or Tags. It generalizes existing synchronization-less Time Difference of Arrival (TDoA) and Time of Arrival (ToA) algorithms. We show how known algorithms can be derived from our new method. A major advantage of our approach is that it provides a comparable or better clock error robustness, i.e. the typical errors of crystal oscillators have negligible impact for TDoA and ToA measurements. We show that our channel usage is for most cases superior compared to the state-of-the art.

Today, many applications such as production or rescue settings rely on highly accurate entity positioning. Advanced Time of Flight (ToF) based positioning methods provide high-accuracy localization of entities. A key challenge for ToF based positioning is to synchronize the clocks between the participating entities.This paper summarizes and analyzes ToA and TDoA methods with respect to clock error robustness. The focus is on synchronization-less methods, i.e. methods which reduce the infrastructure requirement significantly. We introduce a unified notation to survey and compare the relevant work from literature. Then we apply a clock error model and compute worst case location-accuracy errors. Our analysis reveals a superior error robustness against clock errors for so called Double-Pulse methods when applied to radio based ToF positioning.

In this paper, we propose a method to calculate time difference of arrival values between a signal source and several transceivers without the need to synchronize any clocks. The method is allowing the signal source to operate on very low power because it does not need to receive but only has to send short pulses. We derive this new method from an existing protocol, called Whistle, and show how our improvements reduce its error to make the method suitable for radio-based applications. We present a theoretical analysis as well as simulations and first results of an implementation.