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Quantum computers can solve semidefinite programs (SDPs) using resources that scale better than state-of-the-art classical methods as a function of the problem dimension. At the same time, the known quantum algorithms scale very unfavorably in the precision, which makes it non-trivial to find applications for which the quantum methods are well-suited. Arguably, precision is less crucial for SDP relaxations of combinatorial optimization problems (such as the Goemans-Williamson algorithm), because these include a final rounding step that maps SDP solutions to binary variables. With this in mind, Brand\~ao, Fran\c{c}a, and Kueng have proposed to use quantum SDP solvers in order to achieve an end-to-end speed-up for obtaining approximate solutions to combinatorial optimization problems. They did indeed succeed in identifying an algorithm that realizes a polynomial quantum advantage in terms of its asymptotic running time. However, asymptotic results say little about the problem sizes for which advantages manifest. Here, we present an analysis of the non-asymptotic resource requirements of this algorithm. The work consists of two parts. First, we optimize the original algorithm with a particular emphasis on performance for realistic problem instances. In particular, we formulate a version with adaptive step-sizes, an improved detection criterion for infeasible instances, and a more efficient rounding procedure. In a second step, we benchmark both the classical and the quantum version of the algorithm. The benchmarks did not identify a regime where even the optimized quantum algorithm would beat standard classical approaches for input sizes that can be realistically solved at all. In the absence of further significant improvements, these algorithms therefore fall into a category sometimes called galactic: Unbeaten in their asymptotic scaling behavior, but not practical for realistic problems., Comment: 56 pages, 6 figures

The integration of artificial intelligence (AI) in physics education enables novel approaches to data analysis and conceptual learning. A comparative analysis of AI-supported and traditional Excel-based methods reveals distinct strengths and limitations in fostering understanding of pendulum experiments. This study explores the integration of AI-assisted tools, such as a custom chatbot based on ChatGPT, and traditional Excel-based methods in physics education, revealing that while both approaches produce comparable quantitative learning gains, AI tools provide significant qualitative advantages. These include enhanced emotional engagement and higher motivation, highlighting the potential of AI to create a more positive and supportive learning environment. Adaptive AI technologies offer significant promise in supporting structured, data-intensive tasks, emphasizing the necessity for thoughtfully balanced integration into educational practices., Comment: 16 pages, 8 figures

This work explores the integration of AI custom chatbots in educational settings, with a particular focus on their applicability in the context of mathematics and physics. In view of the increasing deployment of AI tools such as ChatGPT in educational contexts, the present study examines their potential as personalized tutoring systems. The study assesses the impact of AI-generated learning materials on the learning experiences and performance of sixth-grade students, with a particular focus on proportional relationships in mathematical and physical contexts. The randomized controlled study with N = 214 students compared traditional textbook materials with explanations generated by a custom chatbot. The results demonstrated that while AI-generated materials had an indefinite impact on learning outcomes, they significantly enhanced positive-activating emotions, situational interest, and self-efficacy, while reducing intrinsic and extrinsic cognitive load. These findings underscore the potential of AI to transform educational practices by fostering a superior learning experience. However, further research is required to clarify its impact on learning performance and long-term learning outcomes. The study highlights the importance of careful integration and customization of AI tools to maximize their benefits in physics education.

The power grid is a critical infrastructure essential for public safety and welfare. As its reliance on digital technologies grows, so do its vulnerabilities to sophisticated cyber threats, which could severely disrupt operations. Effective protective measures, such as intrusion detection and decision support systems, are essential to mitigate these risks. Machine learning offers significant potential in this field, yet its effectiveness is constrained by the limited availability of high-quality data due to confidentiality and access restrictions. To address this, we introduce a simulation environment that replicates the power grid's infrastructure and communication dynamics. This environment enables the modeling of complex, multi-stage cyber attacks and defensive responses, using attack trees to outline attacker strategies and game-theoretic approaches to model defender actions. The framework generates diverse, realistic attack data to train machine learning algorithms for detecting and mitigating cyber threats. It also provides a controlled, flexible platform to evaluate emerging security technologies, including advanced decision support systems. The environment is modular and scalable, facilitating the integration of new scenarios without dependence on external components. It supports scenario generation, data modeling, mapping, power flow simulation, and communication traffic analysis in a cohesive chain, capturing all relevant data for cyber security investigations under consistent conditions. Detailed modeling of communication protocols and grid operations offers insights into attack propagation, while datasets undergo validation in laboratory settings to ensure real-world applicability. These datasets are leveraged to train machine learning models for intrusion detection, focusing on their ability to identify complex attack patterns within power grid operations.

The integration of information and communication technology in distribution grids presents opportunities for active grid operation management, but also increases the need for security against power outages and cyberattacks. This paper examines the impact of cyberattacks on smart grids by replicating the power grid in a secure laboratory environment as a cyber-physical digital twin. A simulation is used to study communication infrastructures for secure operation of smart grids. The cyber-physical digital twin approach combines communication network emulation and power grid simulation in a common modular environment, and is demonstrated through laboratory tests and attack replications.

While anonymity networks such as Tor provide invaluable privacy guarantees to society, they also enable all kinds of criminal activities. Consequently, many blameless citizens shy away from protecting their privacy using such technology for the fear of being associated with criminals. To grasp the potential for alternative privacy protection for those users, we design Seldom, an anonymity network with integrated selective deanonymization that disincentivizes criminal activity. Seldom enables law enforcement agencies to selectively access otherwise anonymized identities of misbehaving users, while providing technical guarantees preventing these access rights from being misused. Seldom further ensures translucency, as each access request is approved by a trustworthy consortium of impartial entities and eventually disclosed to the public (without interfering with ongoing investigations). To demonstrate Seldom's feasibility and applicability, we base our implementation on Tor, the most widely used anonymity network. Our evaluation indicates minimal latency, processing, and bandwidth overheads compared to Tor, while Seldom's main costs stem from storing flow records and encrypted identities. With at most 636 TB of storage required in total to retain the encrypted identifiers of a Tor-sized network for two years, Seldom provides a practical and deployable technical solution to the inherent problem of criminal activities in anonymity networks. As such, Seldom sheds new light on the potentials and limitations when integrating selective deanonymization into anonymity networks.

Internet-wide studies provide extremely valuable insight into how operators manage their Internet of Things (IoT) deployments in reality and often reveal grievances, e.g., significant security issues. However, while IoT devices often use IPv6, past studies resorted to comprehensively scan the IPv4 address space. To fully understand how the IoT and all its services and devices is operated, including IPv6-reachable deployments is inevitable-although scanning the entire IPv6 address space is infeasible. In this paper, we close this gap and examine how to best discover IPv6-reachable IoT deployments. To this end, we propose a methodology that allows combining various IPv6 scan direction approaches to understand the findability and prevalence of IPv6-reachable IoT deployments. Using three sources of active IPv6 addresses and eleven address generators, we discovered 6658 IoT deployments. We derive that the available address sources are a good starting point for finding IoT deployments. Additionally, we show that using two address generators is sufficient to cover most found deployments and save time as well as resources. Assessing the security of the deployments, we surprisingly find similar issues as in the IPv4 Internet, although IPv6 deployments might be newer and generally more up-to-date: Only 39% of deployments have access control in place and only 6.2% make use of TLS inviting attackers, e.g., to eavesdrop sensitive data., Comment: 8 pages, 2 figures

Over the last two decades, research and development efforts have shown that advanced control of heating, ventilation, and air conditioning (HVAC) equipment in commercial buildings can improve energy efficiency, reduce emissions, and turn buildings into active participants in the power grid. Despite these efforts, advanced commercial HVAC control has not yet seen widespread adoption. In this paper, we argue that the research community can help companies deploy advanced HVAC control at speed and scale by reorienting research efforts toward clearly demonstrating the business case for adoption. To support this argument, we draw on findings from the 2023 Intelligent Building Operations Workshop, which brought together researchers, entrepreneurs, and representatives from industry and government to discuss current business offerings, state-of-the-art field demonstrations, barriers to adoption, and future directions.

With critical infrastructure increasingly relying on wireless communication, using end-to-end security such as TLS becomes imperative. However, TLS introduces significant overhead for resource-constrained devices and networks prevalent in critical infrastructure. In this paper, we propose to leverage the degrees of freedom in configuring TLS to dynamically adapt algorithms, parameters, and other settings to best meet the currently occurring resource and security constraints in a wireless communication scenario. Consequently, we can make the best use of scarce resources to provide tightened security for wireless networks in critical infrastructure., Comment: To be published in Proceedings of the 2024 8th Cyber Security in Networking Conference (CSNet)

The industrial landscape is undergoing a significant transformation, moving away from traditional wired fieldbus networks to cutting-edge 5G mobile networks. This transition, extending from local applications to company-wide use and spanning multiple factories, is driven by the promise of low-latency communication and seamless connectivity for various devices in industrial settings. However, besides these tremendous benefits, the integration of 5G as the communication infrastructure in industrial networks introduces a new set of risks and threats to the security of industrial systems. The inherent complexity of 5G systems poses unique challenges for ensuring a secure integration, surpassing those encountered with any technology previously utilized in industrial networks. Most importantly, the distinct characteristics of industrial networks, such as real-time operation, required safety guarantees, and high availability requirements, further complicate this task. As the industrial transition from wired to wireless networks is a relatively new concept, a lack of guidance and recommendations on securely integrating 5G renders many industrial systems vulnerable and exposed to threats associated with 5G. To address this situation, in this paper, we summarize the state-of-the-art and derive a set of recommendations for the secure integration of 5G into industrial networks based on a thorough analysis of the research landscape. Furthermore, we identify opportunities to utilize 5G to enhance security and indicate remaining challenges, identifying future academic directions., Comment: 15 pages, 5 figures

Researchers in the highly active field of intrusion detection largely rely on public datasets for their experimental evaluations. However, the large number of existing datasets, the discovery of previously unknown flaws therein, and the frequent publication of new datasets make it hard to select suitable options and sufficiently understand their respective limitations. Hence, there is a great risk of drawing invalid conclusions from experimental results with respect to detection performance of novel methods in the real world. While there exist various surveys on intrusion detection datasets, they have deficiencies in providing researchers with a profound decision basis since they lack comprehensiveness, actionable details, and up-to-dateness. In this paper, we present COMIDDS, an ongoing effort to comprehensively survey intrusion detection datasets with an unprecedented level of detail, implemented as a website backed by a public GitHub repository. COMIDDS allows researchers to quickly identify suitable datasets depending on their requirements and provides structured and critical information on each dataset, including actual data samples and links to relevant publications. COMIDDS is freely accessible, regularly updated, and open to contributions., Comment: To be published in Proceedings of the 17th Cyber Security Experimentation and Test Workshop (CSET 2024)

With the increasing reliance of smart grids on correctly functioning SCADA systems and their vulnerability to cyberattacks, there is a pressing need for effective security measures. SCADA systems are prone to cyberattacks, posing risks to critical infrastructure. As there is a lack of host-based intrusion detection systems specifically designed for the stable nature of SCADA systems, the objective of this work is to propose a host-based intrusion detection system tailored for SCADA systems in smart grids. The proposed system utilizes USB device identification, flagging, and process memory scanning to monitor and detect anomalies in SCADA systems, providing enhanced security measures. Evaluation in three different scenarios demonstrates the tool's effectiveness in detecting and disabling malware. The proposed approach effectively identifies potential threats and enhances the security of SCADA systems in smart grids, providing a promising solution to protect against cyberattacks.

To meet the requirements of modern production, industrial communication increasingly shifts from wired fieldbus to wireless 5G communication. Besides tremendous benefits, this shift introduces severe novel risks, ranging from limited reliability over new security vulnerabilities to a lack of accountability. To address these risks, we present approaches to (i) prevent attacks through authentication and redundant communication, (ii) detect anomalies and jamming, and (iii) respond to detected attacks through device exclusion and accountability measures., Comment: Accepted to the poster session of the 22nd International Conference on Applied Cryptography and Network Security (ACNS 2024)

Power grids are becoming more digitized, resulting in new opportunities for the grid operation but also new challenges, such as new threats from the cyber-domain. To address these challenges, cybersecurity solutions are being considered in the form of preventive, detective, and reactive measures. Machine learning-based intrusion detection systems are used as part of detection efforts to detect and defend against cyberattacks. However, training and testing data for these systems are often not available or suitable for use in machine learning models for detecting multi-stage cyberattacks in smart grids. In this paper, we propose a method to generate synthetic data using a graph-based approach for training machine learning models in smart grids. We use an abstract form of multi-stage cyberattacks defined via graph formulations and simulate the propagation behavior of attacks in the network. Within the selected scenarios, we observed promising results, but a larger number of scenarios need to be studied to draw a more informed conclusion about the suitability of synthesized data.

The increasing digitization of smart grids has made addressing cybersecurity issues crucial in order to secure the power supply. Anomaly detection has emerged as a key technology for cybersecurity in smart grids, enabling the detection of unknown threats. Many research efforts have proposed various machine-learning-based approaches for anomaly detection in grid operations. However, there is a need for a reproducible and comprehensive evaluation environment to investigate and compare different approaches to anomaly detection. The assessment process is highly dependent on the specific application and requires an evaluation that considers representative datasets from the use case as well as the specific characteristics of the use case. In this work, we present an evaluation environment for anomaly detection methods in smart grids that facilitates reproducible and comprehensive evaluation of different anomaly detection methods., Comment: To be published in Proceedings of 2023 IEEE PES Innovative Smart Grid Technologies Europe (ISGT EUROPE)

The power grid is a critical infrastructure that plays a vital role in modern society. Its availability is of utmost importance, as a loss can endanger human lives. However, with the increasing digitalization of the power grid, it also becomes vulnerable to new cyberattacks that can compromise its availability. To counter these threats, intrusion detection systems are developed and deployed to detect cyberattacks targeting the power grid. Among intrusion detection systems, anomaly detection models based on machine learning have shown potential in detecting unknown attack vectors. However, the scarcity of data for training these models remains a challenge due to confidentiality concerns. To overcome this challenge, this study proposes a model for generating synthetic data of multi-stage cyber attacks in the power grid, using attack trees to model the attacker's sequence of steps and a game-theoretic approach to incorporate the defender's actions. This model aims to create diverse attack data on which machine learning algorithms can be trained.

Aggregation of message authentication codes (MACs) is a proven and efficient method to preserve valuable bandwidth in resource-constrained environments: Instead of appending a long authentication tag to each message, the integrity protection of multiple messages is aggregated into a single tag. However, while such aggregation saves bandwidth, a single lost message typically means that authentication information for multiple messages cannot be verified anymore. With the significant increase of bandwidth-constrained lossy communication, as applications shift towards wireless channels, it thus becomes paramount to study the impact of packet loss on the diverse MAC aggregation schemes proposed over the past 15 years to assess when and how to aggregate message authentication. Therefore, we empirically study all relevant MAC aggregation schemes in the context of lossy channels, investigating achievable goodput improvements, the resulting verification delays, processing overhead, and resilience to denial-of-service attacks. Our analysis shows the importance of carefully choosing and configuring MAC aggregation, as selecting and correctly parameterizing the right scheme can, e.g., improve goodput by 39% to 444%, depending on the scenario. However, since no aggregation scheme performs best in all scenarios, we provide guidelines for network operators to select optimal schemes and parameterizations suiting specific network settings., Comment: accepted at ACNS'24

Industrial control systems increasingly rely on middlebox functionality such as intrusion detection or in-network processing. However, traditional end-to-end security protocols interfere with the necessary access to in-flight data. While recent work on middlebox-aware end-to-end security protocols for the traditional Internet promises to address the dilemma between end-to-end security guarantees and middleboxes, the current state-of-the-art lacks critical features for industrial communication. Most importantly, industrial settings require fine-grained access control for middleboxes to truly operate in a least-privilege mode. Likewise, advanced applications even require that middleboxes can inject specific messages (e.g., emergency shutdowns). Meanwhile, industrial scenarios often expose tight latency and bandwidth constraints not found in the traditional Internet. As the current state-of-the-art misses critical features, we propose Middlebox-aware DTLS (Madtls), a middlebox-aware end-to-end security protocol specifically tailored to the needs of industrial networks. Madtls provides bit-level read and write access control of middleboxes to communicated data with minimal bandwidth and processing overhead, even on constrained hardware., Comment: accepted at AsiaCCS'24

Cyberattacks have grown into a major risk for organizations, with common consequences being data theft, sabotage, and extortion. Since preventive measures do not suffice to repel attacks, timely detection of successful intruders is crucial to stop them from reaching their final goals. For this purpose, many organizations utilize Security Information and Event Management (SIEM) systems to centrally collect security-related events and scan them for attack indicators using expert-written detection rules. However, as we show by analyzing a set of widespread SIEM detection rules, adversaries can evade almost half of them easily, allowing them to perform common malicious actions within an enterprise network without being detected. To remedy these critical detection blind spots, we propose the idea of adaptive misuse detection, which utilizes machine learning to compare incoming events to SIEM rules on the one hand and known-benign events on the other hand to discover successful evasions. Based on this idea, we present AMIDES, an open-source proof-of-concept adaptive misuse detection system. Using four weeks of SIEM events from a large enterprise network and more than 500 hand-crafted evasions, we show that AMIDES successfully detects a majority of these evasions without any false alerts. In addition, AMIDES eases alert analysis by assessing which rules were evaded. Its computational efficiency qualifies AMIDES for real-world operation and hence enables organizations to significantly reduce detection blind spots with moderate effort., Comment: To be published in Proceedings of the 33rd USENIX Security Symposium (USENIX Security 2024)

Industrial systems are increasingly threatened by cyberattacks with potentially disastrous consequences. To counter such attacks, industrial intrusion detection systems strive to timely uncover even the most sophisticated breaches. Due to its criticality for society, this fast-growing field attracts researchers from diverse backgrounds, resulting in 130 new detection approaches in 2021 alone. This huge momentum facilitates the exploration of diverse promising paths but likewise risks fragmenting the research landscape and burying promising progress. Consequently, it needs sound and comprehensible evaluations to mitigate this risk and catalyze efforts into sustainable scientific progress with real-world applicability. In this paper, we therefore systematically analyze the evaluation methodologies of this field to understand the current state of industrial intrusion detection research. Our analysis of 609 publications shows that the rapid growth of this research field has positive and negative consequences. While we observe an increased use of public datasets, publications still only evaluate 1.3 datasets on average, and frequently used benchmarking metrics are ambiguous. At the same time, the adoption of newly developed benchmarking metrics sees little advancement. Finally, our systematic analysis enables us to provide actionable recommendations for all actors involved and thus bring the entire research field forward.

Critical infrastructure constitutes the foundation of every society. While traditionally solely relying on dedicated cable-based communication, this infrastructure rapidly transforms to highly digitized and interconnected systems which increasingly rely on wireless communication. Besides providing tremendous benefits, especially affording the easy, cheap, and flexible interconnection of a large number of assets spread over larger geographic areas, wireless communication in critical infrastructure also raises unique security challenges. Most importantly, the shift from dedicated private wired networks to heterogeneous wireless communication over public and shared networks requires significantly more involved security measures. In this paper, we identify the most relevant challenges resulting from the use of wireless communication in critical infrastructure and use those to identify a comprehensive set of promising opportunities to preserve the high security standards of critical infrastructure even when switching from wired to wireless communication., Comment: Author's version of a paper accepted for publication in Proceedings of the 20th EAI International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (MobiQuitous 2023)