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See detailEphemeriShield - Defence Against Cyber-Antisatellite Weapons
Graczyk, Rafal UL; Volp, Marcus UL

Scientific Conference (2021, October 14)

Mitigating the risks associated with space system operations, especially in Low Earth Orbit, requires a holistic approach, which addresses, in particular, cybersecurity challenges, in addition to meeting ... [more ▼]

Mitigating the risks associated with space system operations, especially in Low Earth Orbit, requires a holistic approach, which addresses, in particular, cybersecurity challenges, in addition to meeting the data acquisition requirements the mission needs. Space traffic management systems form no exception to this rule, but are further constrained by backward compatibility requirements that sometimes are based on decades old foundations. As a result, some space situational awareness systems continue to operate with object catalogues and data dissemination architectures that are prone to failures, not to mention adversarial actions. Proof-of-Concept papers, demonstrating this vulnerability in example attacks on space object ephemerides distribution channels have already been published and show the urgency in rethinking the way we build such high-critical infrastructure. Leveraging recent developments of distributed systems theory and concepts from multi-party consensus in limited-trust environments and in the presence of malicious actors, we designed a more secure system for orbital object ephemerides distribution, ultimately targeting at increasing the safety of satellite operations. This paper presents EphemeriShield, a distributed ephemerides storage and distribution system, aiming at maintaining safety and security guarantees in presence of active attacker or unfortunate fault. Using our EphemeriShield prototype setup, we were able to prove its ability to mask attacks and local faults that otherwise would lead to unnecessary maneuvers. Wide adoption of EphemeriShield may help satellite system operations to become safer and less vulnerable to intentionally adversarial activities, which improves the overall sustainability of space. [less ▲]

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See detailThreat Adaptive Byzantine Fault Tolerant State-Machine Replication
Simoes Silva, Douglas UL; Graczyk, Rafal UL; Decouchant, Jérémie et al

Scientific Conference (2021, September)

Critical infrastructures have to withstand advanced and persistent threats, which can be addressed using Byzantine fault tolerant state-machine replication (BFT-SMR). In practice, unattended cyberdefense ... [more ▼]

Critical infrastructures have to withstand advanced and persistent threats, which can be addressed using Byzantine fault tolerant state-machine replication (BFT-SMR). In practice, unattended cyberdefense systems rely on threat level detectors that synchronously inform them of changing threat levels. How- ever, to have a BFT-SMR protocol operate unattended, the state- of-the-art is still to configure them to withstand the highest possible number of faulty replicas f they might encounter, which limits their performance, or to make the strong assumption that a trusted external reconfiguration service is available, which introduces a single point of failure. In this work, we present ThreatAdaptive the first BFT-SMR protocol that is automatically strengthened or optimized by its replicas in reaction to threat level changes. We first determine under which conditions replicas can safely reconfigure a BFT-SMR system, i.e., adapt the number of replicas n and the fault threshold f, so as to outpace an adversary. Since replicas typically communicate with each other using an asynchronous network they cannot rely on consensus to decide how the system should be reconfigured. ThreatAdaptive avoids this pitfall by proactively preparing the reconfiguration that may be triggered by an increasing threat when it optimizes its performance. Our evaluation shows that ThreatAdaptive can meet the latency and throughput of BFT baselines configured statically for a particular level of threat, and adapt 30% faster than previous methods, which make stronger assumptions to provide safety. [less ▲]

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See detailBridging the space systems performance-reliability gap for future deep space resources exploration and exploitation.
Pinto Gouveia, Ines UL; Graczyk, Rafal UL; Volp, Marcus UL

Poster (2021, April)

In building equipment for space exploitation, one has to trade system robustness for the high processing capabilities and low energy consumption. The high performance, low robustness approach, is ... [more ▼]

In building equipment for space exploitation, one has to trade system robustness for the high processing capabilities and low energy consumption. The high performance, low robustness approach, is acceptable, especially in Earths’ vicinity. However, in more demanding (especially high-radiation) environments, attempts had disappointing outcomes. The processing-reliability gap, between highly reliable and highly performant systems, spans 2-3 orders of magnitude. This gap brings hope, that some of this excess processing power can be utilized, in building a combination of hardware and software mechanisms that is capable of increasing robustness and resilience of otherwise susceptible semiconductor devices, while allowing to harness the remaining processing power to build affordable space systems with large degrees of autonomy, rich functionality and high bandwidth. At the CritiX research group, we aim to bridge this performance-reliability gap, by researching the enabling building blocks for constructing more reliable and more secure System-on-Chips. [less ▲]

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See detailPriLok:Citizen-protecting distributed epidemic tracing
Esteves-Verissimo, Paulo UL; Decouchant, Jérémie UL; Volp, Marcus UL et al

E-print/Working paper (2020)

Contact tracing is an important instrument for national health services to fight epidemics. As part of the COVID-19 situation, many proposals have been made for scaling up contract tracing capacities with ... [more ▼]

Contact tracing is an important instrument for national health services to fight epidemics. As part of the COVID-19 situation, many proposals have been made for scaling up contract tracing capacities with the help of smartphone applications, an important but highly critical endeavor due to the privacy risks involved in such solutions. Extending our previously expressed concern, we clearly articulate in this article, the functional and non-functional requirements that any solution has to meet, when striving to serve, not mere collections of individuals, but the whole of a nation, as required in face of such potentially dangerous epidemics. We present a critical information infrastructure, PriLock, a fully-open preliminary architecture proposal and design draft for privacy preserving contact tracing, which we believe can be constructed in a way to fulfill the former requirements. Our architecture leverages the existing regulated mobile communication infrastructure and builds upon the concept of "checks and balances", requiring a majority of independent players to agree to effect any operation on it, thus preventing abuse of the highly sensitive information that must be collected and processed for efficient contact tracing. This is enforced with a largely decentralised layout and highly resilient state-of-the-art technology, which we explain in the paper, finishing by giving a security, dependability and resilience analysis, showing how it meets the defined requirements, even while the infrastructure is under attack. [less ▲]

Detailed reference viewed: 66 (3 UL)