arXiv subjects

Gergely Biczók

Publications and source records attributed to Gergely Biczók.

14 recordsLinked to original sources

arXiv2026

Cybercrime and Prevention: Colonel Blotto in Social Engineering

Cybercriminals increasingly target the human factor rather than continuously advancing technological defense mechanisms. Consequently, institutions that allocate substantial resources to strengthening their cybersecurity infrastructure may remain vulnerable if a deceived employee voluntarily transmits sensitive information or financial assets to attackers. Therefore, alongside the implementation of technological defense mechanisms, particular emphasis must be placed on mitigating human vulnerabilities, which can be achieved through preventive awareness programs. However, such training activities can only be effective if they are organization- and context-specific. In this paper, we develop two Colonel Blotto game models to determine the optimal allocation of defensive resources across dominant social engineering attack vectors. We ground the models in Routine Activity Theory (RAT), borrowed from criminology, that describes crime as an event involving a motivated offender, a suitable target, and the absence of a capable guardian. Next, we quantify relevant factors via the VIVA (Value, Inertia, Visibility, Accessibility) framework, and operationalize the models by feeding real-world cybercrime data into them. The first model investigates optimal population-level prevention, focusing on nation-states as defenders; we present and compare use cases of three different countries. The second model focuses on the organization as a decision-maker; here, we analyze five use cases involving organizations of different characteristics. Our results demonstrate that theoretically grounded and data-driven models can provide decision support to policymakers and organizational leaders in allocating their efforts optimally to prevent social engineering attacks and improve their overall cyber resilience.

cs.CR↗

arXiv2026

Bribers, Bribers on The Chain, Is Resisting All in Vain? Trustless Consensus Manipulation Through Bribing Contracts

The long-term success of cryptocurrencies largely depends on the incentive compatibility provided to the validators. Bribery attacks, facilitated trustlessly via smart contracts, threaten this foundation. This work introduces, implements, and evaluates three novel and efficient bribery contracts targeting Ethereum validators. The first bribery contract enables a briber to fork the blockchain by buying votes on their proposed blocks. The second contract incentivizes validators to voluntarily exit the consensus protocol, thus increasing the adversary's relative staking power. The third contract builds a trustless bribery market that enables the briber to auction off their manipulative power over the RANDAO, Ethereum's distributed randomness beacon. Finally, we provide an initial game-theoretical analysis of one of the described bribery markets.

cs.CR↗

arXiv2025

Interdependent Privacy in Smart Homes: Hunting for Bystanders in Privacy Policies

Smart home devices such as video doorbells and security cameras are becoming increasingly common in everyday life. While these devices offer convenience and safety, they also raise new privacy concerns: how these devices affect others, like neighbors, visitors, or people passing by. This issue is generally known as interdependent privacy, where one person's actions (or inaction) may impact the privacy of others, and, specifically, bystander privacy in the context of smart homes. Given lax data protection regulations in terms of shared physical spaces and amateur joint data controllers, we expect that the privacy policies of smart home products reflect the missing regulatory incentives. This paper presents a focused privacy policy analysis of 20 video doorbell and smart camera products, concentrating explicitly on the bystander aspect. We show that although some of the vendors acknowledge bystanders, they address it only to the extent of including disclaimers, shifting the ethical responsibility for collecting the data of non-users to the device owner. In addition, we identify and examine real-world cases related to bystander privacy, demonstrating how current deployments can impact non-users. Based on our findings, we analyze vendor privacy policies in light of existing legal frameworks and technical capabilities, and we provide practical recommendations for both policy language and system design to enhance transparency and empower both bystanders and device owners.

cs.CR↗

arXiv2025

Anonymity-washing

Anonymization is a foundational principle of data privacy regulation, yet its practical application remains riddled with ambiguity and inconsistency. This paper introduces the concept of anonymity-washing -- the misrepresentation of the anonymity level of ``sanitized'' personal data -- as a critical privacy concern. While both legal and technical critiques of anonymization exist, they tend to address isolated aspects of the problem. In contrast, this paper offers a comprehensive overview of the conditions that enable anonymity-washing. It synthesizes fragmented legal interpretations, technical misunderstandings, and outdated regulatory guidance and complements them with a systematic review of national and international resources, including legal cases, data protection authority guidelines, and technical documentation. Our findings reveal a lack of coherent support for practitioners, contributing to the persistent misuse of pseudonymization and obsolete anonymization techniques. We conclude by recommending targeted education, clearer technical guidance, and closer cooperation between regulators, researchers, and industry to bridge the gap between legal norms and technical reality.

cs.CR↗

arXiv2025

Realigning Incentives to Build Better Software: a Holistic Approach to Vendor Accountability

In this paper, we ask the question of why the quality of commercial software, in terms of security and safety, does not measure up to that of other (durable) consumer goods we have come to expect. We examine this question through the lens of incentives. We argue that the challenge around better quality software is due in no small part to a sequence of misaligned incentives, the most critical of which being that the harm caused by software problems is by and large shouldered by consumers, not developers. This lack of liability means software vendors have every incentive to rush low-quality software onto the market and no incentive to enhance quality control. Within this context, this paper outlines a holistic technical and policy framework we believe is needed to incentivize better and more secure software development. At the heart of the incentive realignment is the concept of software liability. This framework touches on various components, including legal, technical, and financial, that are needed for software liability to work in practice; some currently exist, some will need to be re-imagined or established. This is primarily a market-driven approach that emphasizes voluntary participation but highlights the role appropriate regulation can play. We connect and contrast this with the EU legal environment and discuss what this framework means for open-source software (OSS) development and emerging AI risks. Moreover, we present a CrowdStrike case study complete with a what-if analysis had our proposed framework been in effect. Our intention is very much to stimulate a robust conversation among both researchers and practitioners.

cs.CR↗

arXiv2025

Modeling interdependent privacy threats

The rise of online social networks, user-gene-rated content, and third-party apps made data sharing an inevitable trend, driven by both user behavior and the commercial value of personal information. As service providers amass vast amounts of data, safeguarding individual privacy has become increasingly challenging. Privacy threat modeling has emerged as a critical tool for identifying and mitigating risks, with methodologies such as LINDDUN, xCOMPASS, and PANOPTIC offering systematic approaches. However, these frameworks primarily focus on threats arising from interactions between a single user and system components, often overlooking interdependent privacy (IDP); the phenomenon where one user's actions affect the privacy of other users and even non-users. IDP risks are particularly pronounced in third-party applications, where platform permissions, APIs, and user behavior can lead to unintended and unconsented data sharing, such as in the Cambridge Analytica case. We argue that existing threat modeling approaches are limited in exposing IDP-related threats, potentially underestimating privacy risks. To bridge this gap, we propose a specialized methodology that explicitly focuses on interdependent privacy. Our contributions are threefold: (i) we identify IDP-specific challenges and limitations in current threat modeling frameworks, (ii) we create IDPA, a threat modeling approach tailored to IDP threats, and (iii) we validate our approach through a case study on WeChat. We believe that IDPA can operate effectively on systems other than third-party apps and may motivate further research on specialized threat modeling.

cs.CR↗

arXiv2024

The Cyber Alliance Game: How Alliances Influence Cyber-Warfare

Cyber-warfare has become the norm in current ongoing military conflicts. Over the past decade, numerous examples have shown the extent to which nation-states become vulnerable if they do not focus on building their cyber capacities. Adding to the inherent complexity of cyberwar scenarios, a state is usually a member of one or more alliances. Alliance policies and internal struggles could shape the individual actions of member states; intuitively, this also holds for the cyber domain. In this paper, we define and study a simple Cyber Alliance Game with the objective of understanding the fundamental influence of alliances on cyber conflicts between nation-states. Specifically, we focus on the decision of whether to exploit a newly found vulnerability individually or share it with the alliance. First, we characterize the impact of vulnerability-sharing rewards on the resulting equilibrium. Second, we study the implications of the internal power structure of alliances on cyberwar outcomes and infer the expected behavior of Dictator, Veto, and Dummy players. Finally, we investigate how alliances can nudge their members via rewards and punishments to adhere to their defensive or offensive cyber policy. We believe that our results contribute to the fundamental understanding of real-world cyber-conflicts by characterizing the impact of alliances.

cs.GT↗

arXiv2024

Incentivizing Secure Software Development: the Role of Voluntary Audit and Liability Waiver

Misaligned incentives in secure software development have long been the focus of research in the economics of security. Product liability, a powerful legal framework in other industries, has been largely ineffective for software products until recent times. However, the rapid regulatory responses to recent global cyber attacks by both the United States and the European Union, together with the (relative) success of the General Data Protection Regulation in defining both duty and standard of care for software vendors, may enable regulators to use liability to re-align incentives for the benefit of the digital society. Specifically, the recent United States National Cybersecurity Strategy suggests shifting responsibility for cyber incidents back to software vendors. In doing so, the strategy also puts forward the concept of the liability waiver: if a software company voluntarily undergoes and passes an IT security audit, its future product liability is (fully or partially) waived. In this paper, we analyze this audit scenario from the perspective of the software vendor and the auditor, respectively. From the vendor's view, this is formulated as a sequential decision problem: a vendor with a product or process needs to pass a mandatory audit to release the product onto the market; it is allowed to go through the audit repeatedly, and thus the vendor needs to determine what level of effort to put into the product following each failed test. We show that the optimal strategy for an opt-in vendor is to never quit and to exert cumulative investments in either a ``one-and-done'' or ``incremental'' manner. From the auditor's view, we examine what type of audit might be the most effective in incentivizing voluntary participation and, at the same time, a more desirable effort from the vendor. We also showed how dynamic audits can be exploited to increase the vendor's incentivizable investment.

cs.CR↗

arXiv2024

IDPFilter: Mitigating Interdependent Privacy Issues in Third-Party Apps

Third-party applications have become an essential part of today's online ecosystem, enhancing the functionality of popular platforms. However, the intensive data exchange underlying their proliferation has increased concerns about interdependent privacy (IDP). This paper provides a comprehensive investigation into the previously underinvestigated IDP issues of third-party apps. Specifically, first, we analyze the permission structure of multiple app platforms, identifying permissions that have the potential to cause interdependent privacy issues by enabling a user to share someone else's personal data with an app. Second, we collect datasets and characterize the extent to which existing apps request these permissions, revealing the relationship between characteristics such as the respective app platform, the app's type, and the number of interdependent privacy-related permissions it requests. Third, we analyze the various reasons IDP is neglected by both data protection regulations and app platforms and then devise principles that should be followed when designing a mitigation solution. Finally, based on these principles and satisfying clearly defined objectives, we propose IDPFilter, a platform-agnostic API that enables application providers to minimize collateral information collection by filtering out data collected from their users but implicating others as data subjects. We implement a proof-of-concept prototype, IDPTextFilter, that implements the filtering logic on textual data, and provide its initial performance evaluation with regard to privacy, accuracy, and efficiency.

cs.CR↗

arXiv2023

Quality Inference in Federated Learning with Secure Aggregation

Federated learning algorithms are developed both for efficiency reasons and to ensure the privacy and confidentiality of personal and business data, respectively. Despite no data being shared explicitly, recent studies showed that the mechanism could still leak sensitive information. Hence, secure aggregation is utilized in many real-world scenarios to prevent attribution to specific participants. In this paper, we focus on the quality of individual training datasets and show that such quality information could be inferred and attributed to specific participants even when secure aggregation is applied. Specifically, through a series of image recognition experiments, we infer the relative quality ordering of participants. Moreover, we apply the inferred quality information to detect misbehaviours, to stabilize training performance, and to measure the individual contributions of participants.

cs.LG↗

arXiv2023

SECREDAS: Safe and (Cyber-)Secure Cooperative and Automated Mobility

Infrastructure-to-Vehicle (I2V) and Vehicle-to-Infrastructure (V2I) communication is likely to be a key-enabling technology for automated driving in the future. Using externally placed sensors, the digital infrastructure can support the vehicle in perceiving surroundings that would otherwise be difficult to perceive due to, for example, high traffic density or bad weather. Conversely, by communicating on-board vehicle measurements, the environment can more accurately be perceived in locations which are not (sufficiently) covered by digital infrastructure. The security of such communication channels is an important topic, since malicious information on these channels could potentially lead to a reduction in overall safety. Collective perception contributes to raising awareness levels and an improved traffic safety. In this work, a demonstrator is introduced, where a variety of novel techniques have been deployed to showcase an overall architecture for improving vehicle and vulnerable road user safety in a connected environment. The developed concepts have been deployed at the Automotive Campus intersection in Helmond (NL), in a field testing setting.

math.OC↗

arXiv2022

In Search of Lost Utility: Private Location Data

The unavailability of training data is a permanent source of much frustration in research, especially when it is due to privacy concerns. This is particularly true for location data since previous techniques all suffer from the inherent sparseness and high dimensionality of location trajectories which render most techniques impractical, resulting in unrealistic traces and unscalable methods. Moreover, time information of location visits is usually dropped, or its resolution is drastically reduced. In this paper we present a novel technique for privately releasing a composite generative model and whole high-dimensional location datasets with detailed time information. To generate high-fidelity synthetic data, we leverage several peculiarities of vehicular mobility such as its language-like characteristics ("you should know a location by the company it keeps") or how humans plan their trips from one point to the other. We model the generator distribution of the dataset by first constructing a variational autoencoder to generate the source and destination locations, and the corresponding timing of trajectories. Next, we compute transition probabilities between locations with a feed forward network, and build a transition graph from the output of this model, which approximates the distribution of all paths between the source and destination (at a given time). Finally, a path is sampled from this distribution with a Markov Chain Monte Carlo method. The generated synthetic dataset is highly realistic, scalable, provides good utility and, nonetheless, provably private. We evaluate our model against two state-of-the-art methods and three real-life datasets demonstrating the benefits of our approach.

cs.CR↗

arXiv2022

Games in the Time of COVID-19: Promoting Mechanism Design for Pandemic Response

Most governments employ a set of quasi-standard measures to fight COVID-19 including wearing masks, social distancing, virus testing, contact tracing, and vaccination. However, combining these measures into an efficient holistic pandemic response instrument is even more involved than anticipated. We argue that some non-trivial factors behind the varying effectiveness of these measures are selfish decision making and the differing national implementations of the response mechanism. In this paper, through simple games, we show the effect of individual incentives on the decisions made with respect to mask wearing, social distancing and vaccination, and how these may result in sub-optimal outcomes. We also demonstrate the responsibility of national authorities in designing these games properly regarding data transparency, the chosen policies and their influence on the preferred outcome. We promote a mechanism design approach: it is in the best interest of every government to carefully balance social good and response costs when implementing their respective pandemic response mechanism; moreover, there is no one-size-fits-all solution when designing an effective solution.

econ.TH↗

arXiv2021

Detecting message modification attacks on the CAN bus with Temporal Convolutional Networks

Multiple attacks have shown that in-vehicle networks have vulnerabilities which can be exploited. Securing the Controller Area Network (CAN) for modern vehicles has become a necessary task for car manufacturers. Some attacks inject potentially large amount of fake messages into the CAN network; however, such attacks are relatively easy to detect. In more sophisticated attacks, the original messages are modified, making the detection a more complex problem. In this paper, we present a novel machine learning based intrusion detection method for CAN networks. We focus on detecting message modification attacks, which do not change the timing patterns of communications. Our proposed temporal convolutional network-based solution can learn the normal behavior of CAN signals and differentiate them from malicious ones. The method is evaluated on multiple CAN-bus message IDs from two public datasets including different types of attacks. Performance results show that our lightweight approach compares favorably to the state-of-the-art unsupervised learning approach, achieving similar or better accuracy for a wide range of scenarios with a significantly lower false positive rate.

cs.CR↗