What a lovely hat

Service discovery is essential in wireless communications. However, existing service discovery protocols provide no or very limited privacy protection for service providers and clients, and they often leak sensitive information (e.g., service type, client’s identity and mobility pattern), which leads to various network-based attacks (e.g., spoofing, man-in-the-middle, identification and tracking). In this paper, we propose a private service discovery protocol, called PriSrv, which allows a...

In this paper, we investigate whether the privacy mechanism of periodically changing the pseudorandom identities of Bluetooth Low Energy (BLE) beacons is sufficient to ensure privacy. We consider a new natural privacy notion for BLE broadcasting beacons which we call ``Timed-sequence- indistinguishability'' of beacons. This new privacy definition is stronger than the well-known indistinguishability, since it considers not just the advertisements' content, but also the advertisements'...

Relay attacks pose a serious security threat to wireless systems, such as, contactless payment systems, keyless entry systems, or smart access control systems. Distance bounding protocols, which allow an entity to not only authenticate another entity but also determine whether it is physically close by, effectively mitigate relay attacks. However, secure implementation of distance bounding protocols, especially of the time critical challenge-response phase, has been a challenging task. In...

To combat the ongoing Covid-19 pandemic, many new ways have been proposed on how to automate the process of finding infected people, also called contact tracing. A special focus was put on preserving the privacy of users. Bluetooth Low Energy (BLE) as base technology has the most promising properties, so this survey focuses on automated contact tracing techniques using BLE. We define multiple classes of methods and identify two major groups: systems that rely on a server for finding new...

Contact tracing is among the most important interventions to mitigate the spread of any pandemic, usually in the form of manual contact tracing. Smartphone-facilitated digital contact tracing may help to increase tracing capabilities and extend the coverage to those contacts one does not know in person. Most implemented protocols use local Bluetooth Low Energy (BLE) communication to detect contagion-relevant proximity, together with cryptographic protections, as necessary to improve the...

Mass surveillance can be more easily achieved leveraging fear and desire of the population to feel protected while affected by devastating events. Indeed, in such scenarios, governments can adopt exceptional measures that limit civil rights, usually receiving large support from citizens. The COVID-19 pandemic is currently affecting daily life of many citizens in the world. People are forced to stay home for several weeks, unemployment rates quickly increase, uncertainty and sadness...

The specification of Bluetooth and Bluetooth Low Energy includes dedicated encryption key negotiation protocols used by two parties to agree on the entropy of encryption keys. In this work, we show that an attacker can manipulate the entropy negotiation of Bluetooth and Bluetooth Low Energy to drastically reduce the encryption key space. We call our attack the Key Negotiation Of Bluetooth (KNOB) attack. In the case of Bluetooth, we demonstrate that the entropy can be reduced from 16 to 1...