Biblio

This paper presents LIRA-V, a lightweight system for performing remote attestation between constrained devices using the RISC-V architecture. We propose using read-only memory and the RISC-V Physical Memory Protection (PMP) primitive to build a trust anchor for remote attestation and secure channel creation. Moreover, we show how LIRA-V can be used for trusted communication between two devices using mutual attestation. We present the design, implementation and evaluation of LIRA-V using an off-the-shelf RISC-V microcontroller and present performance results to demonstrate its suitability. To our knowledge, we present the first remote attestation mechanism suitable for constrained RISC-V devices, with applications to cyber-physical systems and Internet of Things (IoT) devices.

Underpinning the operation of Bitcoin is a peer-to-peer (P2P) network [1] that facilitates the execution of transactions by end users, as well as the transaction confirmation process known as bitcoin mining. The security of this P2P network is vital for the currency to function and subversion of the underlying network can lead to attacks on bitcoin users including theft of bitcoins, manipulation of the mining process and denial of service (DoS). As part of this paper the network protocol and bitcoin core software are analysed, with three bitcoin message exchanges (the connection handshake, GETHEADERS/HEADERS and MEMPOOL/INV) found to be potentially vulnerable to spoofing and use in distributed denial of service (DDoS) attacks. Possible solutions to the identified weaknesses and vulnerabilities are evaluated, such as the introduction of random nonces into network messages exchanges.

Traditional countermeasures to relay attacks are difficult to implement on mobile devices due to hardware limitations. Establishing proximity of a payment device and terminal is the central notion of most relay attack countermeasures, and mobile devices offer new and exciting possibilities in this area of research. One such possibility is the use of on-board sensors to measure ambient data at both the payment device and terminal, with a comparison made to ascertain whether the device and terminal are in close proximity. This project focuses on the iPhone, specifically the iPhone 6S, and the potential use of its sensors to both establish proximity to a payment terminal and protect Apple Pay against relay attacks. The iPhone contains 12 sensors in total, but constraints introduced by payment schemes mean only 5 were deemed suitable to be used for this study. A series of mock transactions and relay attack attempts are enacted using an iOS application written specifically for this study. Sensor data is recorded, and then analysed to ascertain its accuracy and suitability for both proximity detection and relay attack countermeasures.

In the field of smartphones a number of proposals suggest that sensing the ambient environment can act as an effective anti-relay mechanism. However, existing literature is not compliant with industry standards (e.g. EMV and ITSO) that require transactions to complete within a certain time-frame (e.g. 500ms in the case of EMV contactless payments). In previous work the generation of an artificial ambient environment (AAE), and especially the use of infrared light as an AAE actuator was shown to have high success rate in relay attacks detection. In this paper we investigate the application of infrared as a relay attack detection technique in various scenarios, namely, contactless transactions (mobile payments, transportation ticketing, and physical access control), and continuous Two-Factor Authentication. Operating requirements and architectures are proposed for each scenario, while taking into account industry imposed performance requirements, where applicable. Protocols for integrating the solution into the aforementioned scenarios are being proposed, and formally verified. The impact on the performance is assessed through practical implementation. Proposed protocols are verified using Scyther, a formal mechanical verification tool. Finally, additional scenarios, in which this technique can be applied to prevent relay or other types of attacks, are discussed.