Passengers information in public transport and privacy: Can anonymous tickets prevent tracking?

Abstract Modern public transportation companies often record large amounts of information. Privacy can be safeguarded by discarding nominal tickets, or introducing anonymization techniques. But is anonymity at all possible when everything is recorded? In this paper we discuss travel information management in the public transport scenario and we present a revealing case study (relative to the city of Cesena, Italy), showing that even anonymous 10-ride bus tickets may betray a user's privacy expectations. We also propose a number of recommendations for the design and management of public transport information systems, aimed at preserving the users’ privacy, while retaining the useful analysis features enabled by the e-ticketing technology

Privacy-aware multi-context RFID infrastructure using public key cryptography

We propose a novel RFID infrastructure design, which foresees the usage of a single RFID tag within different contexts and for multiple purposes. We show that an infrastructure for multi-purpose RFID tags to be used in different contexts can be implemented in a privacy-preserving manner. We address security attacks such as impersonation, tracking, and replay. We also introduce spatio-temporal attacks as an important threat against privacy. We propose a methodology to thwart or alleviate these kinds of attacks. We develop our multi-context RFID infrastructure relying on usage of public key cryptography (PKC), which presents more scalable solutions in the sense that the backend servers can identify the tags 75 times faster than best symmetric cipher based systems when there are a million tags in the system. We demonstrate that the requirements for PKC are comparable to those for other cryptographic implementations based on symmetric ciphers proposed for RFID use

Private and Secure Public-Key Distance Bounding: Application to NFC Payment

Distance-Bounding is used to defeat relay attacks. For wireless payment systems, the payment terminal is not always online. So, the protocol must rely on a public key for the prover (payer). We propose a generic transformation of a (weakly secure) symmetric distance bounding protocol which has no post-verification into wide-strong-private and secure public-key distance bounding

Optimal Proximity Proofs Revisited

Distance bounding protocols become important since wireless technologies become more and more common. Therefore, the security of the distance bounding protocol should be carefully analyzed. However, most of the protocols are not secure or their security is proven informally. Recently, Boureanu and Vaudenay defined the common structure which is commonly followed by most of the distance bounding protocols: answers to challenges are accepted if they are correct and on time. They further analyzed the optimal security that we can achieve in this structure and proposed DBopt which reaches the optimal security bounds. In this paper, we define three new structures: when the prover registers the time of a challenge, when the verifier randomizes the sending time of the challenge, and the combined structure. Then, we show the optimal security bounds against distance fraud and mafia fraud which are lower than the bounds showed by Boureanu and Vaudenay for the common structure. Finally, we adapt the DBopt protocol according to our new structures and we get three new distance bounding protocols. All of them are proven formally. In the end, we compare the performance of the new protocols with DBopt and we see that we have a better efficiency. For instance, we can reduce the number of rounds in DB2 (one of the instances of DBopt) from $123$ to $5$ with the same security

Formal Analysis of Distance Bounding with Secure Hardware

A distance bounding (DB) protocol is a two-party authentication protocol between a prover and a verifier which is based on the distance between the prover and the verifier. It aims to defeat threats by malicious provers who try to convince that they are closer to the verifier or adversaries which seek to impersonate a far-away prover. All these threats are covered in several security definitions and it is not possible to have a single definition covering all. In this paper, we describe a new DB model with three parties where the new party is named hardware. In this model, called secure hardware model (SHM), the hardware is held by the prover without being able to tamper with. We define an all-in-one security model which covers all the threats of DB and an appropriate privacy notion for SHM. In the end, we construct the most efficient (in terms of computation by the prover-hardware and number of rounds) and secure DB protocols achieving the optimal security bounds as well as privacy