arXiv subjects

Stefan Rass

Publications and source records attributed to Stefan Rass.

At least 19 recordsLinked to original sources

arXiv2026

Methods for Uncertainty Representation in Risk Management: A Comparative Review and Decision-Oriented Framework

The consideration of uncertainty is a central but frequently inadequately addressed component of risk management. A systematic treatment of uncertainty is essential for ensuring the quality and traceability of decision-making processes, particularly in complex and safety-critical environments. This review systematically analyzes how established risk management approaches conceptualize and represent uncertainty in both their theoretical foundations and practical applications. Based on a systematic literature review of 370 publications, the identified approaches are classified into five methodological families. These include probabilistic methods, evidence-based and fuzzy-logic approaches, qualitative elicitation techniques, graphical and visual representations and hybrid frameworks. The analysis shows that probabilistic methods remain predominant due to their quantitative rigor, whereas fuzzy and evidence-based approaches are particularly suited to addressing vagueness and epistemic uncertainty. Qualitative and graphical approaches are found to enhance interpretive understanding and support the transparent communication of uncertainty. Despite these developments, the analysis indicates that the practical integration of these approaches into operational risk management remains limited in many domains. The findings highlight the need for more structured guidance in method selection and suggest that future research would benefit from further development of hybrid approaches and visualization techniques.

q-fin.RM↗

arXiv2026

Synthetic APTs: the Collapse of TTP-Based Attribution

Cyber Threat Intelligence CTI attribution relies on identifying the Tactics, Techniques, and Procedures TTPs that distinguish one threat actor from another. This approach presupposes that each adversary leaves a recognizable operational fingerprint. This work investigates whether AI driven adversary emulation challenges that presupposition. We deploy agents from our Cybersecurity SuperIntelligence CSI framework, configured as five Advanced Persistent Threat APT groups, APT28, APT29, APT41, APT44, and Lazarus Group, against AI driven Defender agents across two cyber ranges provided by CYBER RANGES, equipped with defensive software Wazuh, Velociraptor, Elasticsearch and active AI driven defenders: an enterprise network and a military infrastructure. Across 20 experiments using two defender models, a binary pattern emerges: all 10 Enterprise range experiments resulted in compromise 2 to 12 hosts per experiment, while all 10 Military range experiments were successfully defended or resulted in stalemates, regardless of APT profile or defender model. In 8 of 10 Enterprise experiments, attackers independently weaponized the defender's own Velociraptor endpoint management platform as a command and control channel, a convergent behavior not encoded in any threat intelligence profile. We argue that in the AI era, wherein agents can be deployed provided the right models are available and subject to the right scaffolding and agentic configuration, the entry barrier for operating like a nation state APT collapses: beyond nation states, individuals can now act like commonly identified threat actors, and with it, fundamentally undermine TTP based attribution.

cs.CR↗

arXiv2026

Security Incentivization: An Empirical Study of how Micropayments Impact Code Security

Security often receives insufficient developer attention because it does not directly generate visible value, leading to underinvestment in practice. We evaluate a countermeasure by team-level incentives tied to measurable security improvements over time. Our semi-automated mechanism aggregates static analysis findings from Bearer, Detekt, and mobsfscan, computes security issue density, and rewards teams based on the relative improvement ratio across sprints, enabling repeatable, scriptable reporting at scale. In a controlled course experiment with 84 students across 14 teams, we compared a security-incentivized condition, in which bonus points were linked to security scanner results, against a control condition with an otherwise identical grading scheme. The treatment group achieved significantly lower security issue density overall (beta regression: $\beta = -0.396, p = 0.0342$), indicating improved measurable security under incentivization. After controlling for platform, we observed a marked front-end/back-end disparity, with back-ends showing fewer issues and higher improvement ratios under incentives, highlighting heterogeneous effects across stack layers. Notably, these gains were not the byproduct of inflated code volume, as lines of code increased similarly across groups over time. The measurement pipeline and toolchain proved feasible for scripting and automation, supporting scalable adoption in practice. Our results suggest that aligning rewards with automated security metrics can measurably improve code security and merit follow-up in professional contexts and longer development lifecycles.

cs.CR↗

arXiv2026

Plausible Deniability in Fully Homomorphic Computation

We introduce \emph{Plausible Deniability in Fully Homomorphic Computation} (PD-FHC), a framework enabling users to outsource Boolean computations to an untrusted cloud while maintaining both computational privacy against honest-but-curious providers and plausible deniability against coercive adversaries. We define the notion of a \emph{Deniable Computation Medium} (DCM) and a \emph{Deniable Computation Scheme} (DCS) as medium-independent abstractions, then instantiate them using RGB images with Fredkin-gate circuits. One real circuit and several decoys share a single fixed Fredkin-gate wiring. Embedded control bits decide what each gate computes at each pixel, so the same wiring evaluates the real function at the real positions and decoy functions elsewhere. The cloud applies this one wiring to every pixel identically, processing all circuits in a single pass. Under coercion, the user reveals a decoy with verifiable results while the real circuit stays hidden. We formalize multi-round coercion games with existence and circuit-discovery advantages. For the image instantiation, we prove \emph{information-theoretic position privacy} under a \emph{matched-marginal condition}: when the real, decoy, and fill bits are drawn from a common per-position law and placed at random, the embedded LSB plane is exchangeable, so an honest-but-curious provider gains no advantage over guessing at locating the real positions, for any such law and not only the uniform one. We are explicit that this is a condition Alice enforces, that it is distinct from steganalytic undetectability, and that the latter requires the embedded law to match the declared service's legitimate-input law.

cs.CR↗

arXiv2026

A Stackelberg Model for Hybridization in Cryptography

Similar to a strategic interaction between rational and intelligent agents, cryptography problems can be examined through the prism of game theory. In this setting, the agent aiming to protect a message is called the defender, while the one attempting to decrypt it, generally for malicious purposes, is the attacker. To strengthen security in cryptography, various strategies have been developed, among which hybridization stands out as a key concept in modern cryptographic design. This strategy allows the defender to select among different encryption algorithms (classical, post-quantum, or hybrid) while carefully balancing security and operational costs. On the other side, the attacker, limited by available resources, chooses cryptanalysis methods capable of breaching the selected algorithm. We model this interaction as a Stackelberg cryptographic hybridization problem under resource constraints. Here, the defender randomizes over encryption algorithms, and the attacker observes the choice before selecting suitable cryptanalysis methods. The attacker's decision is framed as a conditional optimization problem, which we refer to as the ``attacker subgame''. We then propose a dynamic programming approach for the attacker's subgame, while the defender's Stackelberg optimization is formulated as a linear program.

cs.CR↗

arXiv2026

Game-Theoretic Modeling of Stealthy Intrusion Defense against MDP-Based Attackers

The rapid expansion of Internet use has increased system exposure to cyber threats, with advanced persistent threats (APTs) being especially challenging due to their stealth, prolonged duration, and multi-stage attacks targeting high-value assets. In this study, we model APT evolution as a strategic interaction between an attacker and a defender on an attack graph. With limited information about the attacker's position and progress, the defender acts at random intervals by deploying intrusion detection sensors across the network. Once a compromise is detected, affected components are immediately secured through measures such as backdoor removal, patching, or system reconfiguration. Meanwhile, the attacker begins with reconnaissance and then proceeds through the network, exploiting vulnerabilities and installing backdoors to maintain persistent access and adaptive movement. Furthermore, the attacker may take several steps between consecutive defensive operations, resulting in an asymmetric temporal dynamic. The defender's goal is to reduce the likelihood that the attacker will gain access to a critical asset, whereas the attacker's purpose is to increase this likelihood. We investigate this interaction under three informational regimes, reflecting varying levels of attacker knowledge prior to action: (i) a Stackelberg scenario, in which the attacker has full knowledge of the defender's strategy and can optimize accordingly; (ii) a blind regime, where the attacker has no information and assumes uniform beliefs about defensive deployments; and (iii) a belief-based framework, where the attacker holds accurate probabilistic beliefs about the defender's actions. For each regime, we derive optimal defensive strategies by solving the corresponding optimization problems.

cs.CR↗

arXiv2026

Post-Quantum Sanitizable Signatures from McEliece-Based Chameleon Hashing

We introduce a novel post-quantum sanitizable signature scheme constructed upon a chameleon hash function derived from the McEliece cryptosystem. In this design, the designated sanitizer possesses the inherent trapdoor of a Goppa code, which facilitates controlled collision-finding via Patterson decoding. This mechanism enables authorized modification of specific message blocks while ensuring all other content remains immutably bound. We provide formal security definitions and rigorous proofs of existential unforgeability and immutability, grounded in the hardness of syndrome decoding in the random-oracle model, where a robust random oracle thwarts trivial linear hash collisions. A key innovation lies in our precise characterization of the transparency property: by imposing a specific weight constraint on the randomizers generated by the signer, we achieve perfect transparency, rendering sanitized signatures indistinguishable from freshly signed ones. This work establishes the first transparent, code-based, post-quantum sanitizable signature scheme, offering strong theoretical guarantees and a pathway for practical deployment in long-term secure applications.

cs.CR↗

arXiv2026

Towards Cybersecurity Superintelligence: from AI-guided humans to human-guided AI

Cybersecurity superintelligence -- artificial intelligence exceeding the best human capability in both speed and strategic reasoning -- represents the next frontier in security. This paper documents the emergence of such capability through three major contributions that have pioneered the field of AI Security. First, PentestGPT (2023) established LLM-guided penetration testing, achieving 228.6% improvement over baseline models through an architecture that externalizes security expertise into natural language guidance. Second, Cybersecurity AI (CAI, 2025) demonstrated automated expert-level performance, operating 3,600x faster than humans while reducing costs 156-fold, validated through #1 rankings at international competitions including the $50,000 Neurogrid CTF prize. Third, Generative Cut-the-Rope (G-CTR, 2026) introduces a neurosymbolic architecture embedding game-theoretic reasoning into LLM-based agents: symbolic equilibrium computation augments neural inference, doubling success rates while reducing behavioral variance 5.2x and achieving 2:1 advantage over non-strategic AI in Attack & Defense scenarios. Together, these advances establish a clear progression from AI-guided humans to human-guided game-theoretic cybersecurity superintelligence.

cs.CR↗

arXiv2026

Cybersecurity AI: A Game-Theoretic AI for Guiding Attack and Defense

AI-driven penetration testing now executes thousands of actions per hour but still lacks the strategic intuition humans apply in competitive security. To build cybersecurity superintelligence --Cybersecurity AI exceeding best human capability-such strategic intuition must be embedded into agentic reasoning processes. We present Generative Cut-the-Rope (G-CTR), a game-theoretic guidance layer that extracts attack graphs from agent's context, computes Nash equilibria with effort-aware scoring, and feeds a concise digest back into the LLM loop \emph{guiding} the agent's actions. Across five real-world exercises, G-CTR matches 70--90% of expert graph structure while running 60--245x faster and over 140x cheaper than manual analysis. In a 44-run cyber-range, adding the digest lifts success from 20.0% to 42.9%, cuts cost-per-success by 2.7x, and reduces behavioral variance by 5.2x. In Attack-and-Defense exercises, a shared digest produces the Purple agent, winning roughly 2:1 over the LLM-only baseline and 3.7:1 over independently guided teams. This closed-loop guidance is what produces the breakthrough: it reduces ambiguity, collapses the LLM's search space, suppresses hallucinations, and keeps the model anchored to the most relevant parts of the problem, yielding large gains in success rate, consistency, and reliability.

cs.CR↗

arXiv2025

Cybersecurity AI: Evaluating Agentic Cybersecurity in Attack/Defense CTFs

We empirically evaluate whether AI systems are more effective at attacking or defending in cybersecurity. Using CAI (Cybersecurity AI)'s parallel execution framework, we deployed autonomous agents in 23 Attack/Defense CTF battlegrounds. Statistical analysis reveals defensive agents achieve 54.3% unconstrained patching success versus 28.3% offensive initial access (p=0.0193), but this advantage disappears under operational constraints: when defense requires maintaining availability (23.9%) and preventing all intrusions (15.2%), no significant difference exists (p>0.05). Exploratory taxonomy analysis suggests potential patterns in vulnerability exploitation, though limited sample sizes preclude definitive conclusions. This study provides the first controlled empirical evidence challenging claims of AI attacker advantage, demonstrating that defensive effectiveness critically depends on success criteria, a nuance absent from conceptual analyses but essential for deployment. These findings underscore the urgency for defenders to adopt open-source Cybersecurity AI frameworks to maintain security equilibrium against accelerating offensive automation.

cs.CR↗

arXiv2025

On Unique Neighborhoods in Bipartite and Expander Graphs

An undirected graph is said to have \emph{unique neighborhoods} if any two distinct nodes have also distinct sets of neighbors. In this way, the connections of a node to other nodes can characterize a node like an "identity", irrespectively of how nodes are named, as long as two nodes are distinguishable. We study the uniqueness of neighborhoods in (random) bipartite graphs, and expander graphs.

math.CO↗

arXiv2025

Koney: A Cyber Deception Orchestration Framework for Kubernetes

System operators responsible for protecting software applications remain hesitant to implement cyber deception technology, including methods that place traps to catch attackers, despite its proven benefits. Overcoming their concerns removes a barrier that currently hinders industry adoption of deception technology. Our work introduces deception policy documents to describe deception technology "as code" and pairs them with Koney, a Kubernetes operator, which facilitates the setup, rotation, monitoring, and removal of traps in Kubernetes. We leverage cloud-native technologies, such as service meshes and eBPF, to automatically add traps to containerized software applications, without having access to the source code. We focus specifically on operational properties, such as maintainability, scalability, and simplicity, which we consider essential to accelerate the adoption of cyber deception technology and to facilitate further research on cyber deception.

cs.CR↗

arXiv2025

CAI: An Open, Bug Bounty-Ready Cybersecurity AI

By 2028 most cybersecurity actions will be autonomous, with humans teleoperating. We present the first classification of autonomy levels in cybersecurity and introduce Cybersecurity AI (CAI), an open-source framework that democratizes advanced security testing through specialized AI agents. Through rigorous empirical evaluation, we demonstrate that CAI consistently outperforms state-of-the-art results in CTF benchmarks, solving challenges across diverse categories with significantly greater efficiency -up to 3,600x faster than humans in specific tasks and averaging 11x faster overall. CAI achieved first place among AI teams and secured a top-20 position worldwide in the "AI vs Human" CTF live Challenge, earning a monetary reward of $750. Based on our results, we argue against LLM-vendor claims about limited security capabilities. Beyond cybersecurity competitions, CAI demonstrates real-world effectiveness, reaching top-30 in Spain and top-500 worldwide on Hack The Box within a week, while dramatically reducing security testing costs by an average of 156x. Our framework transcends theoretical benchmarks by enabling non-professionals to discover significant security bugs (CVSS 4.3-7.5) at rates comparable to experts during bug bounty exercises. By combining modular agent design with seamless tool integration and human oversight (HITL), CAI addresses critical market gaps, offering organizations of all sizes access to AI-powered bug bounty security testing previously available only to well-resourced firms -thereby challenging the oligopolistic ecosystem currently dominated by major bug bounty platforms.

cs.CR↗

arXiv2025

Statistically Testing Training Data for Unwanted Error Patterns using Rule-Oriented Regression

Artificial intelligence models trained from data can only be as good as the underlying data is. Biases in training data propagating through to the output of a machine learning model are a well-documented and well-understood phenomenon, but the machinery to prevent these undesired effects is much less developed. Efforts to ensure data is clean during collection, such as using bias-aware sampling, are most effective when the entity controlling data collection also trains the AI. In cases where the data is already available, how do we find out if the data was already manipulated, i.e., ``poisoned'', so that an undesired behavior would be trained into a machine learning model? This is a challenge fundamentally different to (just) improving approximation accuracy or efficiency, and we provide a method to test training data for flaws, to establish a trustworthy ground-truth for a subsequent training of machine learning models (of any kind). Unlike the well-studied problem of approximating data using fuzzy rules that are generated from the data, our method hinges on a prior definition of rules to happen before seeing the data to be tested. Therefore, the proposed method can also discover hidden error patterns, which may also have substantial influence. Our approach extends the abilities of conventional statistical testing by letting the ``test-condition'' be any Boolean condition to describe a pattern in the data, whose presence we wish to determine. The method puts fuzzy inference into a regression model, to get the best of the two: explainability from fuzzy logic with statistical properties and diagnostics from the regression, and finally also being applicable to ``small data'', hence not requiring large datasets as deep learning methods do. We provide an open source implementation for demonstration and experiments.

cs.LG↗

arXiv2024

Honeyquest: Rapidly Measuring the Enticingness of Cyber Deception Techniques with Code-based Questionnaires

Fooling adversaries with traps such as honeytokens can slow down cyber attacks and create strong indicators of compromise. Unfortunately, cyber deception techniques are often poorly specified. Also, realistically measuring their effectiveness requires a well-exposed software system together with a production-ready implementation of these techniques. This makes rapid prototyping challenging. Our work translates 13 previously researched and 12 self-defined techniques into a high-level, machine-readable specification. Our open-source tool, Honeyquest, allows researchers to quickly evaluate the enticingness of deception techniques without implementing them. We test the enticingness of 25 cyber deception techniques and 19 true security risks in an experiment with 47 humans. We successfully replicate the goals of previous work with many consistent findings, but without a time-consuming implementation of these techniques on real computer systems. We provide valuable insights for the design of enticing deception and also show that the presence of cyber deception can significantly reduce the risk that adversaries will find a true security risk by about 22% on average.

cs.CR↗

arXiv2024

PentestGPT: An LLM-empowered Automatic Penetration Testing Tool

Penetration testing, a crucial industrial practice for ensuring system security, has traditionally resisted automation due to the extensive expertise required by human professionals. Large Language Models (LLMs) have shown significant advancements in various domains, and their emergent abilities suggest their potential to revolutionize industries. In this research, we evaluate the performance of LLMs on real-world penetration testing tasks using a robust benchmark created from test machines with platforms. Our findings reveal that while LLMs demonstrate proficiency in specific sub-tasks within the penetration testing process, such as using testing tools, interpreting outputs, and proposing subsequent actions, they also encounter difficulties maintaining an integrated understanding of the overall testing scenario. In response to these insights, we introduce PentestGPT, an LLM-empowered automatic penetration testing tool that leverages the abundant domain knowledge inherent in LLMs. PentestGPT is meticulously designed with three self-interacting modules, each addressing individual sub-tasks of penetration testing, to mitigate the challenges related to context loss. Our evaluation shows that PentestGPT not only outperforms LLMs with a task-completion increase of 228.6\% compared to the \gptthree model among the benchmark targets but also proves effective in tackling real-world penetration testing challenges. Having been open-sourced on GitHub, PentestGPT has garnered over 4,700 stars and fostered active community engagement, attesting to its value and impact in both the academic and industrial spheres.

cs.SE↗

arXiv2024

Application Layer Cyber Deception without Developer Interaction

Cyber deception techniques that are tightly intertwined with applications pose significant technical challenges in production systems. Security measures are usually the responsibility of a system operator, but they are typically limited to accessing built software artifacts, not their source code. This limitation makes it particularly challenging to deploy cyber deception techniques at application runtime and without full control over the software development lifecycle. This work reviews 19 technical methods to accomplish this and evaluates them based on technical, topological, operational, and efficacy properties. We find some novel techniques beyond honeypots and reverse proxies that seem to have received little research interest despite their promise for cyber deception. We believe that overcoming these technical challenges can drive the adoption of more dynamic and personalized cyber deception techniques, tailored to specific classes of applications.

cs.CR↗

arXiv2024

RobotPerf: An Open-Source, Vendor-Agnostic, Benchmarking Suite for Evaluating Robotics Computing System Performance

We introduce RobotPerf, a vendor-agnostic benchmarking suite designed to evaluate robotics computing performance across a diverse range of hardware platforms using ROS 2 as its common baseline. The suite encompasses ROS 2 packages covering the full robotics pipeline and integrates two distinct benchmarking approaches: black-box testing, which measures performance by eliminating upper layers and replacing them with a test application, and grey-box testing, an application-specific measure that observes internal system states with minimal interference. Our benchmarking framework provides ready-to-use tools and is easily adaptable for the assessment of custom ROS 2 computational graphs. Drawing from the knowledge of leading robot architects and system architecture experts, RobotPerf establishes a standardized approach to robotics benchmarking. As an open-source initiative, RobotPerf remains committed to evolving with community input to advance the future of hardware-accelerated robotics.

cs.RO↗