Detection and prevention of global navigation satellite system (GNSS) “spoofing” attacks, or the broadcast of false global navigation satellite system services, has recently attracted much research interest. This survey aims to fill three gaps in the literature: first, to assess in detail the exact nature of threat scenarios posed by spoofing against the most commonly cited targets; second, to investigate the many practical impediments, often underplayed, to carrying out GNSS spoofing attacks in the field; and third, to survey and assess the effectiveness of a wide range of proposed defences against GNSS spoofing. Our conclusion lists promising areas of future research.

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An exchange or payment protocol is considered fair if neither of the two parties exchanging items or payment a t a n y time during the protocol has a signiaecant advantage over the other entity. Fairness is an important property for electronic commerce. This paper identiaees a design framework based on existing fair protocols which use oaeine trusted third parties, but with convertible signatures as the underlying mechanism. We show that in principle any convertible signature scheme can be used to design a fair payment protocol. A speciaec protocol is detailed based on RSA undeniable signatures which is more eaecient than other similar fair payment s c hemes. Furthermore, in this protocol the aenal signature obtained is always an ordinary RSA signature.

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Industrial control systems (ICS) are moving from dedicated communications to switched and routed corporate networks, exposing them to the Internet and placing them at risk of cyber-attacks. Existing methods of detecting cyberattacks, such as intrusion detection systems (IDSs), are commonly implemented in ICS and SCADA networks. However, these devices do not detect more complex threats that manifest themselves gradually over a period of time through a combination of unusual sequencing of activities, such as process-related attacks. During the normal operation of ICSs, ICS devices record device logs, capturing their industrial processes over time. These logs are a rich source of information that should be analysed in order to detect such process-related attacks. In this paper, we present a novel process mining anomaly detection method for identifying anomalous behaviour and cyber-attacks using ICS data logs and the conformance checking analysis technique from the process mining discipline. A conformance checking analysis uses logs captured from production systems with a process model (which captures the expected behaviours of a system) to determine the extent to which real behaviours (captured in the logs) matches the expected behaviours (captured in the process model). The contributions of this paper include an experimentally derived recommendation for logging practices on ICS devices, for the purpose of process miningbased analysis; a formalised approach for pre-processing and transforming device logs from ICS systems into event logs suitable for process mining analysis; guidance on how to create a process model for ICSs and how to apply the created process model through a conformance checking analysis to identify anomalous behaviours. Our anomaly detection method has been successfully applied in detecting ICS cyber-attacks, which the widely used IDS Snort does not detect, using logs derived from industry standard ICS devices.

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a b s t r a c t Supervisory Control and Data Acquisition (SCADA) systems are one of the key foundations of smart grids. The Distributed Network Protocol version 3 (DNP3) is a standard SCADA protocol designed to facilitate communications in substations and smart grid nodes. The protocol is embedded with a security mechanism called Secure Authentication (DNP3-SA). This mechanism ensures that end-to-end communication security is provided in substations. This paper presents a formal model for the behavioural analysis of DNP3-SA using Coloured Petri Nets (CPN). Our DNP3-SA CPN model is capable of testing and verifying various attack scenarios: modification, replay and spoofing, combined complex attack and mitigation strategies. Using the model has revealed a previously unidentified flaw in the DNP3-SA protocol that can be exploited by an attacker that has access to the network interconnecting DNP3 devices. An attacker can launch a successful attack on an outstation without possessing the pre-shared keys by replaying a previously authenticated command with arbitrary parameters. We propose an update to the DNP3-SA protocol that removes the flaw and prevents such attacks. The update is validated and verified using our CPN model proving the effectiveness of the model and importance of the formal protocol analysis.

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