Authentication in conventional networks (like the Internet) is usually based upon something you know (e.g., a password), something you have (e.g., a smartcard) or something you are (biometrics). In mobile ad-hoc networks, location information can also be used to authenticate devices and users. We will focus on how a prover can securely show that (s)he is within a certain distance to a verifier. Brands and Chaum proposed the distance bounding protocol as a secure solution for this problem. However, this protocol is vulnerable to a socalled "terrorist fraud attack". In this paper, we will explain how to modify the distance bounding protocol to make it resistant to this kind of attacks. Recently, two other secure distance bounding protocols were published. We will discuss the properties of these protocols and show how to use it as a building block in a location verification scheme.

Implantable Medical Devices (IMDs) typically use proprietary protocols with no or limited security to wirelessly communicate with a device programmer. These protocols enable doctors to carry out critical functions, such as changing the IMD's therapy or collecting telemetry data, without having to perform surgery on the patient. In this paper, we fully reverse-engineer the proprietary communication protocol between a device programmer and the latest generation of a widely used Implantable Cardioverter Defibrillator (ICD) which communicate over a long-range RF channel (from two to five meters). For this we follow a black-box reverse-engineering approach and use inexpensive Commercial Off-The-Shelf (COTS) equipment. We demonstrate that reverse-engineering is feasible by a weak adversary who has limited resources and capabilities without physical access to the devices. Our analysis of the proprietary protocol results in the identification of several protocol and implementation weaknesses. Unlike previous studies, which found no security measures, this article discovers the first known attempt to obfuscate the data that is transmitted over the air. Furthermore, we conduct privacy and Denial-of-Service (DoS) attacks and give evidence of other attacks that can compromise the patient's safety. All these attacks can be performed without needing to be in close proximity to the patient. We validate that our findings apply to (at least) 10 types of ICDs that are currently on the market. Finally, we propose several practical short-and long-term countermeasures to mitigate or prevent existing vulnerabilities.

Abstract. Location information can be used to enhance mutual entity authentication protocols in wireless ad-hoc networks. More specifically, distance bounding protocols have been introduced by Brands and Chaum at Eurocrypt'93 to preclude distance fraud and mafia fraud attacks, in which a local impersonator exploits a remote honest user. Hancke and Kuhn have extended these protocols to cope with noisy channels. This paper presents an improved distance bounding protocol for noisy channels that offers a substantial reduction in the number of communication rounds compared to the Hancke and Kuhn protocol. The main idea is to use binary codes to correct bit errors occurring during the fast bit exchanges. Our protocol is perfectly suitable to be employed in noisy wireless environments such as RFID.

The emergence of pervasive computing devices has raised several privacy issues. In this paper, we address the risk of tracking attacks in RFID networks. Our contribution is threefold: (1) We repair three revised EC-RAC protocols of Lee, Batina and Verbauwhede and show that two of the improved authentication protocols are wide-strong privacypreserving and one wide-weak privacy-preserving; (2) We present the search protocol, a novel scheme which allows for privately querying a particular tag, and proof its security properties; and (3) We design a hardware architecture to demonstrate the implementation feasibility of our proposed solutions for a passive RFID tag. Due to the specific design of our authentication protocols, they can be realized with an area significantly smaller than other RFID schemes proposed in the literature, while still achieving the required security and privacy properties.