Cryptography and Security
Botnet Detection on CTU-13 Using Lightweight Machine Learning Models
Subhash Gurappa, Yashas Hariprasad, Sundararaj Sitharama Iyengar et al. (+1 more)
Botnets are among the most persistent cyber threats, enabling large-scale attacks such as spam, credential theft, and distributed denial-of-service (DDoS). While deep learning approaches have recently been applied to botnet detection, they are computationally intensive and often lack interpretability. We present a comparative study of lightweight machine learning models including Logistic Regression, Decision Tree, and Random Forest on the CTU-13
dataset, a
benchmark for botnet traffic analysis. We extract interpretable flow-based features and evaluate each model on detection accuracy, precision, recall, F1 score, and feature importance. Results demonstrate that lightweight models can achieve competitive detection performance with minimal computational cost, while also offering interpretability critical for forensic investigation. On CTU-13, our Random Forest achieves a PR-AUC of approximately 0.54 and ROC-AUC of 0.97 while training over 90% faster than published CNN baselines. These results demonstrate that lightweight models can match or exceed deep-learning performance under natural class imbalance while maintaining interpretability and low computational cost.
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All authors Subhash Gurappa, Yashas Hariprasad, Sundararaj Sitharama Iyengar, Naveen Kumar Chaudhary
Cryptography and Security
Beyond Zero: Enterprise Security for the AI Era
Joseph Valente and Michal Zalewski
The rise of autonomous AI
agents and the accelerating velocity of corporate data access are stretching the application-centric model of zero trust security to its breaking point. This paper introduces Beyond Zero, a new security paradigm designed for the AI era. The Beyond Zero architecture performs per-resource and method access decisions for humans and
agents at machine speed. By shrinking the trust boundary from the application level to the individual action, and by coupling static authorization guarantees with dynamic, AI-driven
reasoning, Beyond Zero enables a self-defending enterprise capable of mediating thousands of human and machine decisions per second. This paper outlines Google's
vision for the future of this access model as well a call for industry collaboration and standards development.
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Cryptography and Security
TriSweep: A Four-Drone Swarm Framework for Electromagnetic Side-Channel Analysis
Eric Yocam and Varghese Vaidyan
Electromagnetic (EM) side-channel analysis traditionally assumes a stationary, close-proximity probe - a threat model that underestimates aerial adversaries. TriSweep is a simulation framework that designs and evaluates a four-drone swarm architecture for autonomous standoff EM-SCA of embedded microcontrollers at 0.25-1.5 m. Three spatially specialized collector drones - Anchor (full-spectrum), Mask Probe (mask-register loading leakage), and Cipher Probe (masked SubBytes output leakage) - feed a stationary Accumulator drone that performs coherent combining (+4.8 dB SNR gain) and second-order mask cancellation via a centered product of the two spatially separated leakage streams. Evaluated against three real ANSSI ASCAD
datasets (ATmega8515 masked AES-128 and 50/100-sample desynchronized variants), the framework achieves a simulated key rank of 18 +/- 1.7 (five-seed) at 0.25 m on the primary masked
dataset. Profiling-trace cross-correlation
alignment reduces single-drone rank from 89 to 21 on the 100-sample-jitter variant, demonstrating compensation for drone hover vibration. A two-channel CNN in the Accumulator converges to a loss of 0.454 (vs. random baseline 5.545) and improves rank on desynchronized
datasets. No physical hardware has been fabricated; prototype construction is the planned next step.
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Cryptography and Security
UNAD+: An Explainable Hybrid Framework for Unknown Network Attack Detection
Saif Alzubi and Frederic Stahl
The detection of previously unseen network attacks remains a major challenge for intrusion detection systems. Although supervised learning methods often perform well on known attack classes, they are limited when new attack types are not represented in the training data. Unsupervised methods are more suitable for detecting zero-day attacks, as they do not require labelled attack samples, but they often suffer from high false positive rates, which limits their real-world usefulness. This paper presents UNAD+, an enhanced framework for unknown network attack detection derived from the previously proposed Unknown Network Attack Detector (UNAD). UNAD+ combines a benign-only unsupervised ensemble with Weighted Majority Voting (WMV), a supervised refinement stage trained on pseudo-labelled detections, and a post hoc explainability layer that provides both local and global explanations. The framework was evaluated on the CICIDS2017 and NSL-KDD
benchmark datasets. The results show that UNAD+ improves on the original UNAD framework, achieving F1-scores above 98% across the
benchmark datasets while significantly reducing false positives and enhancing transparency and deployment suitability through integrated explainability.
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Cryptography and Security
Innovations in Cardless Artificial Intelligence Banking: A Comprehensive Framework for Cyber Secure and Fraud Mitigation using Machine Learning Algorithms
Md Israfeel
The advent of cardless artificial intelligence (AI) banking heralds a paradigm shift in the financial landscape, offering users unprecedented security and convenience. This paper outlines a comprehensive framework designed to enhance cybersecurity, introduce auto-generated virtual cards, and mitigate fraud risks within cardless AI banking systems. The framework envisions a future banking architecture that employs AI-powered data cryptography to create secure virtual cards for seamless transactions. By emphasizing secure communication channels, it ensures the integrity of financial activities among banking systems, cardholders, and third-party vendors. AI-based authorization methodologies play a pivotal role in authenticating each transaction while proactively identifying potential fraud, demonstrating the framework's efficacy in fortifying cardless AI banking security. The initial approach, featuring an AI-driven, feature-based banking system, ensures the generation of virtual cards with encrypted data, minimizing information exposure and reducing fraud risks. Integrating a machine learning
algorithm adds an additional layer of protection against potential fraudulent activities. In conclusion, the proposed framework establishes a holistic cybersecurity and fraud-mitigation paradigm for cardless AI banking systems. Its implementation empowers financial institutions to address security concerns associated with traditional banking, paving the way for a future banking landscape that is not only fraud-resistant but also secure and convenient for users.
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Cryptography and Security
Building an Open Source Operational Technology Pentesting Platform: Lessons from LINICS
Awais Rashid, Joseph Gardiner and Louise Evans
Information Technology (IT) security professionals have ready access to open-source platforms such as Kali Linux. But no such platform exists for Operational Technology (OT) that underpins Industrial Control Systems. We discuss experiences of architecting, building and releasing LINICS, an open-source platform for OT pentesting and security analysis.
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Cryptography and Security
A Formal Basis for Quantum Cryptographic Exposure Measurement under HNDL Threat
Matheus Rufino, Rafael Duarte Marcelino and Julio Smanioto Garcia
An adversary copies your encrypted traffic today and waits for a
quantum computer to decrypt it later. How exposed are you? We show that the functional form of the answer is not merely a calibration choice – it is structurally justified by three assumptions about
adversarial production and value-decay dynamics. Under those assumptions, the HNDL compromise probability factorises into a temporal hazard, a multiplicative cryptographic-vulnerability and operational-exposure term, and a saturation denominator governed by the defense-attack intensity ratio; the marginal sensitivity to each dimension is endogenous to the organisation's position in the vulnerability-exposure plane, not a fixed global constant. Additive scoring frameworks cannot reproduce this structure because the interaction between cryptographic vulnerability and operational exposure is absent by construction, regardless of calibration. The resulting framework provides a structurally grounded basis for operational HNDL exposure prioritisation under partial observability.
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Cryptography and Security
Measuring Security Without Fooling Ourselves: Why Benchmarking Agents Is Hard
Sahar Abdelnabi, Chris Hicks, Konrad Rieck et al. (+1 more)
The
benchmarks used to evaluate AI
agents in security-critical roles suffer from crucial weaknesses. Building on recent empirical evidence, we characterize three core challenges that undermine security evaluations:
benchmark vulnerabilities, temporal staleness, and runtime uncertainty. We then outline practical directions toward building more robust and trustworthy evaluation frameworks.
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All authors Sahar Abdelnabi, Chris Hicks, Konrad Rieck, Ahmad-Reza Sadeghi
Cryptography and Security
EnCAgg: Enhanced Clustering Aggregation for Robust Federated Learning against Dynamic Model Poisoning
Tianyun Zhang, Zhen Yang, Haozhao Wang et al. (+2 more)
Federated learning faces increasing threats from model poisoning attacks, which harms its application to improve
privacy. Existing defense methods typically rely on fixed thresholds or perform clustering with a fixed number of clusters to distinguish malicious gradients from benign ones. However, these methods are difficult to adapt to dynamic poisoning strategies of malicious clients, and often result in the loss of benign gradients due to the heterogeneity of clients' local
datasets. To address these problems, we propose a novel robust aggregation method that leverages a small number of known benign clients as references, enabling accurate identification and filtering of malicious gradients while retaining as many benign gradients as possible, even when the number of malicious clients is unknown and variable. First, we introduce a density-based low-dimensional gradient clustering method, which projects gradients onto the two most divergent dimensions and applies density-based clustering to identify malicious gradients while retaining clustered benign gradients and potentially benign outliers. Second, we design an enhancing clustering low-dimensional gradient generator model, which learns to generate pseudo-gradients aligned with the boundary of the benign cluster. These pseudo-gradients act as bridges to connect sparse benign gradient outliers. Third, we introduce low-dimensional gradient re-clustering that clusters the generated pseudo-gradients together with real gradients to recover benign gradients misclassified as noise points, enabling more benign gradients to participate in aggregation. Extensive experiments on the MNIST, CIFAR-10, and MIND
datasets demonstrate that our method exhibits superior fidelity and robustness under dynamic poisoning scenarios.
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All authors Tianyun Zhang, Zhen Yang, Haozhao Wang, Ru Zhang, Yongfeng Huang
Cryptography and Security
Exact Hidden Paths in Noisy High Dimensional Path Spaces
Victor Duarte Melo
We introduce a mathematical and cryptographic framework for exact recovery of noisy hidden paths in high dimensional discrete path spaces. The work is inspired by the path integral viewpoint, where global quantities arise from contributions over many possible trajectories. Instead of approximating a global path sum, we study the inverse problem of recovering one exact hidden trajectory from incomplete, noisy, projected, and aggregated observables. The hidden object is a planted discrete path whose transitions may include macro steps, microscopic perturbations, and discrete noise. Public information is represented by large observable vectors rather than short hash digests, since excessive compression would bound the effective recovery problem by the digest size. We formalize several recovery notions, including planted exact recovery, arbitrary witness recovery, canonical recovery, quotient recovery, and recovery of derived encodings. The main distinction is that approximate reconstruction and exact recovery are fundamentally different tasks. A method may reveal coarse geometry or dominant regions without recovering the precise microscopic sequence defining the hidden path. We also discuss attack surfaces relevant to future cryptographic use, including linearization,
lattice style recovery, dynamic programming, meet in the middle attacks, SAT and SMT formulations, approximation followed by rounding, witness collisions, and generic
quantum search. This work does not claim a complete post
quantum cryptosystem. It provides a formal framework for studying exact hidden path recovery as a possible foundation for future cryptographic constructions
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Cryptography and Security
A Constant-Time Implementation Methodology for Activation Functions on Microcontrollers
Andrii Tyvodar, Andreas Rechberger, Dirmanto Jap et al. (+4 more)
Embedded neural-network inference can leak information through timing side channels, including leakage caused by the evaluation of activation functions. This work proposes a constant-time implementation methodology for activation functions on embedded microcontrollers and validates it on ReLU, sigmoid, tanh, GELU, and Swish on an ARM Cortex-M4 platform. The proposed methodology combines branchless selection, fixed-cost Padé-based approximation, dummy arithmetic where needed, and cycle
alignment to obtain timing-regular activation-function implementations. As motivation, we also evaluate a desynchronization-based countermeasure and show that it remains vulnerable to a template-based timing attack. Experimental results show that the resulting protected implementations achieve identical cycle counts for all tested inputs, including (88) cycles in the three-function setting and (108) cycles in the five-function setting. At the same time, the numerical-error analysis indicates that the approximated nonlinear functions retain high accuracy. These results suggest that the proposed methodology provides a practical basis for constructing side-channel-resistant activation functions in embedded inference.
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All authors Andrii Tyvodar, Andreas Rechberger, Dirmanto Jap, Shivam Bhasin, Bernhard Jungk, Jakub Breier, Xiaolu Hou
Cryptography and Security
Characterizing the Fault Response of the Intel Neural Compute Stick 2 Under Single-Pulse Electromagnetic Fault Injection
Štefan Kučerák, Jakub Breier and Xiaolu Hou
Vision processing units and other commercial neural-network inference accelerators are increasingly deployed in safety-relevant edge applications, but their fault response under transient hardware disturbances remains poorly characterized in the open literature. For the Intel Movidius Myriad X, packaged as the Intel Neural Compute Stick 2 (NCS2), only a single feasibility study has been published. We report a systematic single-pulse electromagnetic fault injection (EMFI) campaign on the NCS2 running three ImageNet-trained convolutional neural networks (ResNet-18, ResNet-50, VGG-11) on the OpenVINO runtime. Across 1,536 spot-test trials at characterized hotspots and approximately 16,000 parameter-search trials, single pulses produce four reproducible outcome classes: no measured accuracy change, minor silent data corruption, major persistent degradation that survives across subsequent inferences until model reload, and device hangs requiring USB power-cycling; these outcomes are respectively interpreted as no-effect, SDC with possible SET-like or small persistent-state mechanisms, SEU-like persistent corruption, and SEFI-like loss of functionality. Two findings are central. First, the major-degradation class can be induced at 18-31% of trials at characterized hotspots, with post-collapse top-1 accuracy below five percent and persistence across all subsequent inferences until explicit model reload - a regime that no inference-API-level mechanism detects. Second, this regime is also inducible by pulses delivered to an idle device with the model already loaded, demonstrating that load-time integrity checks alone are insufficient. We discuss mitigation strategies graded by class, focusing on mechanisms implementable at the application level without modification to the device firmware or the OpenVINO runtime.
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Cryptography and Security
TimeGuard: Channel-wise Pool Training for Backdoor Defense in Time Series Forecasting
Quang Duc Nguyen, Siyuan Liang, Yiming Li et al. (+2 more)
Time Series
Forecasting (TSF) is highly vulnerable to
backdoor attacks, yet effective defenses remain underexplored due to challenges arising from data
entanglement and shifts in task formulation. To fill this gap, we conduct a systematic evaluation of thirteen representative
backdoor defenses across the TSF life cycle and analyze their failure modes. Our results reveal two fundamental issues: (1) data
entanglement induces channel-level signal dilution, rendering sample-filtering and trigger-synthesis defenses ineffective at localizing
backdoors; and (2) task-formulation shift leads to training-loss degeneration, causing poisoned and clean windows to become indistinguishable at training stages. Based on these findings, we propose a training-time
backdoor defense for TSF, termed TimeGuard. Our method adopts channel-wise pool training as the core paradigm and initializes a high-confidence pool using time-aware criteria to mitigate signal dilution. Moreover, we introduce distance-regularized loss selection to progressively expand the reliable pool during training and ease loss degeneration. Extensive experiments across multiple
datasets,
forecasting architectures, and TSF
backdoor attacks demonstrate that TimeGuard substantially improves robustness, boosting $\mathrm{MAE}_\mathrm{P}$ by $1.96\times$ over the leading baseline, while preserving clean performance within 5% $\mathrm{MAE}_\mathrm{C}$.
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All authors Quang Duc Nguyen, Siyuan Liang, Yiming Li, Fushuo Huo, Dacheng Tao
Cryptography and Security
A First Measurement Study on Authentication Security in Real-World Remote MCP Servers
Huijun Zhou, Xiaohan Zhang, Haozhe Zhang et al. (+3 more)
The Model Context Protocol (MCP) is emerging as a common interface connecting large
language models (LLMs) with external services. Remote deployments are becoming increasingly important as
agents connect to user-linked online services, such as social, productivity, and financial services. In such deployments, the authentication boundary between MCP clients and remote servers becomes security-critical, yet remains underexplored. We present the first measurement study of authentication security in real-world remote MCP servers. We identify 7,973 live remote MCP servers, finding that 40.55% expose tools without authentication. Among authenticated servers, OAuth is the dominant authorization mechanism for reaching remote services, and OAuth deployments in the MCP ecosystem commonly exhibit three characteristics: open client environments, dynamic client registration, and delegated authorization. These characteristics distinguish MCP deployments from traditional OAuth and introduce new attack surfaces. Guided by this observation, we derive a taxonomy of authentication flaws comprising three MCP-specific categories and conventional OAuth misconfigurations, for a total of four categories and nine concrete flaw types. To evaluate these flaws at scale, we implement a semi-automated detection framework that combines passive traffic inspection with active dynamic probing. Applying it to 119 testable real-world OAuth-enabled MCP servers, we find that each server exhibits at least one flaw, with a total of 325 flaws identified, among which dynamic client registration flaws affect 96.6% of tested servers. Many of these flaws can lead to sensitive information leakage and account takeover. Through responsible disclosure, we obtained 9 CVE IDs. Our findings expose pervasive authentication weaknesses in the MCP ecosystem and underscore the urgent need for hardened OAuth-based remote deployments.
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All authors Huijun Zhou, Xiaohan Zhang, Haozhe Zhang, Haoyang Zhang, Mi Zhang, Min Yang
Cryptography and Security
Building Europe's Quantum Shield: The Strategic view for a Continent-Wide Quantum Key Distribution (QKD) Infrastructure
Leandros Maglaras, Ilias Papastamatiou, Alexios Aivaliotis et al. (+2 more)
The fast growth of
quantum computing can lead to amazing scientific breakthroughs while on the same time can be used to break today's security systems, raising new risks for existing digital systems. Facing this challenge, the European's Union's deployement of the European Communication Infrastructure (EuroQCI) is crucial. The SEEWQCI project combines fiber cables, satellite communications and enhanced security rules to build a strong digital shield. Its focus is to protect vital services like power grids and hospitals keeping Europeans' data safe.
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All authors Leandros Maglaras, Ilias Papastamatiou, Alexios Aivaliotis, Evangelos Markatos, Konstantinos Karantzalos
Cryptography and Security
STRAL: What Adaptation Gains, Loses, and Costs in SOC Alert Screening
Samuel Ndichu, Tao Ban, Seiichi Ozawa et al. (+1 more)
Security-alert screening must balance false-alert burden against missed important events, yet adaptation can change which events are detected. We investigate this trade-off using STRAL, a score-triggered active-learning controller combining ADWIN monitoring, selective label acquisition, and bounded model updates, with an optional historical validation Guard. Across four chronological alert-stream settings, we compare adaptive screening with a fixed, non-adapting baseline (Frozen), measuring recall, false-alert burden, detection preservation, and label-query costs. On two AMiner settings, STRAL reduces false positives by 21.4% (14 to 11) and 16.7% (6 to 5), respectively, while preserving all Frozen detections. On Wazuh, Guard reduces false positives by 9.8% (522 to 471), while losing two Frozen detections. On NAD-CD, STRAL raises recall from 36.11% to 40.29%, but loses 40.1% of Frozen detections while gaining 3,000 others; false positives increase by 151.2%. Guard preserves Frozen decisions on NAD-CD but requires 3,550 label queries, compared with 2,000 for STRAL. These findings demonstrate why adaptive SOC screening must be evaluated through detection preservation, false-alert burden, and feedback cost alongside aggregate recall.
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All authors Samuel Ndichu, Tao Ban, Seiichi Ozawa, Takeshi Takahashi
Cryptography and Security
ASEval: Automated Trajectory-Level Security Testing for Autonomous Agents
Jianan Ma, Xiaohu Du, Ruixiao Lin et al. (+9 more)
As autonomous
agents (e.g., OpenClaw) increasingly operate with deep system-level privileges to execute complex tasks, they introduce severe, unmitigated security risks. Existing LLM safety testing methods are largely built around
prompt-level inputs and response-level judgments, while recent
agent benchmarks remain limited in automation, trajectory coverage, and action-grounded judgment. In this work, we present ASEval, a novel automated security testing framework for autonomous
agents. ASEval generates realistic benign multi-turn conversations, perturbs them into risk test cases through carefully designed perturbation operators, executes each case against the target
agent, and applies an action-grounded oracle to judge the complete trace. We instantiate ASEval to construct A3S-Bench, a test suite of 2,254 executable multi-turn test cases spanning diverse usage scenarios, delivery patterns, and
agent-level security risks. Extensive evaluation on 11 LLM-backed OpenClaw
agents confirms that ASEval effectively exposes pervasive security failures. In particular, our proposed perturbation operators raise the average risk-trigger rate from 22.9% under existing injection techniques to 47.4%, as judged by an action-grounded oracle that matches human annotation at 93.2% binary F1. Our further analysis and case studies illustrate that such failures emerge from multi-turn delivery, persistent state, and tool-mediated actions that response-level evaluation overlooks.
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All authors Jianan Ma, Xiaohu Du, Ruixiao Lin, Yaoxiang Bian, Jialuo Chen, Yunhao Feng, Xiaofang Yang, Shiwen Cui, Changhua Meng, Xinhao Deng, Jingyi Wang, Zhen Wang
Cryptography and Security
Decision-Aware Quadratic ReLU Replacement for HE-Friendly Inference
Rui Li, Wenyuan Wu and Weijie Miao
Fully homomorphic encryption (FHE) supports only additions and multiplications, so FHE-only neural-network inference typically replaces ReLU with
polynomials fitted over empirical activation intervals. Such interval fitting often requires higher-degree
polynomials to control activation error, incurring homomorphic evaluation costs, while classification is determined by the final logit decision. We revisit ReLU replacement from a decision-aware perspective: given a trained single-hidden-layer ReLU MLP and a specified calibration set, can an HE-friendly low-degree
polynomial replace ReLU without retraining while preserving calibration-set decisions? We focus on quadratic replacement, the lowest-degree that retains a genuine per-unit nonlinearity. For calibration sets positive-margin separable in the lifted space, we formulate quadratic replacement as a linear separation problem, yielding necessary and sufficient conditions for calibration-lossless replacement and a constructive
algorithm for the coefficients. When the positive-margin condition fails – often because a few near-boundary or misclassified calibration samples bring the lifted hulls into contact – we extend the same
geometric framework via reduced convex hulls and Lagrangian-dual soft-margin relaxations. These cap the weight any single sample can carry, converting the problem into smaller convex quadratic programs that yield approximately feasible coefficients with high empirical agreement on calibration-set decisions. In particular, at the maximal weight cap $\mu=1$, the reduced-convex-hull relaxation reduces to standard convex-hull separation; the relaxation thus continuously extends the positive-margin exact theory. Under CKKS, the quadratic replacement matches plaintext top-1 accuracy on multiple
benchmarks, running 3.7–4.1$\times$ faster than Remez-7 in the activation module and 1.18–1.68$\times$ faster end-to-end.
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Cryptography and Security
Market-Analysis-Driven Methodology for Assessing Charging Station Cybersecurity
Jakob Löw, Lukas Eder, Alexander Müller et al. (+1 more)
Modern charging communication standards for electric vehicles include optional security controls such as TLS-based authentication and encryption. However, with tens of thousands of fast charging points deployed in any given country, individually testing each one for security control support is infeasible. This paper proposes a scalable, extrapolation-based methodology for assessing charging station cybersecurity at a national level. A
market analysis identifies operator-manufacturer pairs, enabling the targeted selection of charging stations for field testing, whose results can then be extrapolated to all stations sharing the same combination. We demonstrate this methodology for Germany, covering over 40000 CCS charging points as of December 2025. With a manageable number of field tests, our extrapolated data examines 51.9% of german CCS charging stations. It shows that only 27.4% of charging stations in our scope provide TLS-protected communication, despite widespread theoretical support.
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All authors Jakob Löw, Lukas Eder, Alexander Müller, Hans-Joachim Hof
Cryptography and Security
Adversarial Trust Poisoning in Vehicular Collaborative Perception
Yutong Liu, Chenyi Wang, Ming F. Li et al. (+1 more)
Collaborative perception (CP) enables connected and autonomous vehicles to share sensor data and jointly reason about their environment. To defend against adversaries that fabricate or manipulate shared data, existing systems employ cross-vehicle inconsistency detection and trust estimation, penalizing vehicles whose observations conflict with the majority. In this work, we show that these defenses themselves introduce a new attack surface. We present TrustFlip, a novel attack that weaponizes consistency-based defenses to poison the trust assigned to benign vehicles. Instead of injecting false data into the collaboration pipeline, it deploys physical
adversarial objects that are genuine but induce inconsistent observations among benign vehicles. The resulting inconsistencies are misattributed by the defense to the targeted vehicle, causing its trust score to degrade and eventually leading to its downweighting or exclusion from collaboration. Consequently, the system loses reliable sensing contributors, degrading perception capability and potentially inducing safety-critical failures. We evaluate TrustFlip across multiple collaborative perception architectures and defense mechanisms. Our results show that state-of-the-art defenses can be significantly affected: the attack removes the targeted benign vehicle from collaboration in up to 87.7% of scenarios and drops Average Precision (AP) by up to 13%. As an initial mitigation, we introduce TrustReflect, a lightweight self-reflection mechanism that marks disputed regions as uncertain and excludes them from trust evaluation, reducing the attack success rate by 35-100%.
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All authors Yutong Liu, Chenyi Wang, Ming F. Li, Qingzhao Zhang
Cryptography and Security
Human Vulnerability Assessment in Cybersecurity: A Systematic Literature Review of Methods, Models, and Instruments
Dimitra Papatsaroucha, Stavroula Psaroudaki, Eleftheria Vassilaki et al. (+4 more)
In cybersecurity, vulnerability assessment has typically focused on identifying and measuring vulnerabilities within digital assets and technical infrastructures. However, there is growing recognition that this approach alone is inadequate without a structured examination of the human factor, which is becoming more frequently targeted and manipulated by cyber adversaries. Human vulnerabilities extend beyond individual susceptibility to cyber threats, encompassing a wide array of psychological, cognitive, behavioral, social, and contextual factors that can, whether unintentionally or intentionally, jeopardize the security and integrity of systems and data. Despite this recognition, human vulnerability assessment remains fragmented, often addressed from a static rather than a dynamic perspective, and with limited focus on the ways it propagates across individuals and systems; a growing body of literature has explored specific facets of the issue, including one-time assessments of security behavior, user awareness, and, to a degree, intentional insider threats and their detection. This research offers a systematic literature review (SLR) of Human Vulnerability Assessment (HVA) in cybersecurity, including methods, models, and instruments proposed for the conceptual or practical assessment of human vulnerabilities across various dimensions. Following the PRISMA framework, this review gathers relevant studies published from 2017 to 2025, aiming to investigate whether any assessment methods, models, or instruments exist that address the entire spectrum of human vulnerabilities dynamically. The findings highlight gaps and limitations in current proposed solutions and identify areas for further investigation regarding holistic assessment that simultaneously and dynamically considers the entire spectrum of both the unintentional and intentional dimensions of human vulnerability.
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All authors Dimitra Papatsaroucha, Stavroula Psaroudaki, Eleftheria Vassilaki, Konstantina Pityanou, Michail Alexandros Kourtis, Ilias Politis, Evangelos K. Markakis
Cryptography and Security
QT-PUF: Quantum Tunneling Leakage Based PUF for Implantable IoMT Devices
Yueqi Ma, Vivek Mohan, Chip-Hong Chang et al. (+1 more)
The Internet of Medical Things (IoMT) marks a shift toward decentralized healthcare, enabling continuous monitoring and personalized care through connected wearable and implantable devices. However, ensuring the trust and integrity of these devices themselves remains a major challenge, as physical compromise or counterfeiting can directly endanger patient safety,
privacy, and data integrity. This work presents QT-PUF, a gate-tunneling-leakage-based physical unclonable function (PUF) that leverages
quantum-mechanical gate leakage resulting from process-induced variations in standard CMOS devices. A differential readout
circuit with a pseudo-resistor I-to-V frontend is proposed to convert the picoampere-level leakage variations into digital responses. Unlike existing PUFs such as those based on
memory, ring oscillators, or arbiters, which are less suitable for ultralow-power IoMT devices (due to additional circuitry, power overhead, or poor stability), QT-PUF requires no external excitation or stabilization and operates under static bias. Simulation-based measurements for a $\mathbf{65}$~nm CMOS process demonstrate an
entropy of $\mathbf{0.9999998}$, an FHD of $\mathbf{0.5001}$, and an average power (energy) consumption of $\mathbf{96.04}$~nW/bit ($\mathbf{19.21}$~fJ/bit, respectively) at $\mathbf{1.2\,V}$ and $\mathbf{35\,^{\circ}C}$ for the proposed PUF. It operates reliably across $\mathbf{0.9}\text{--}\mathbf{1.3}$~V and $\mathbf{0}\text{--}\mathbf{100\,^{\circ}C}$ with an average BER below $\mathbf{0.000163}$ across $\mathbf{1.0}\text{--}\mathbf{1.3}$~V and $\mathbf{10}\text{--}\mathbf{70\,^{\circ}C}$ within the operating conditions of typical implantable devices.
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All authors Yueqi Ma, Vivek Mohan, Chip-Hong Chang, Emmanuel M. Drakakis
Cryptography and Security · Cross-listed from cs.SE
Automated Repair of TEE Partitioning Issues via DSL-Guided and LLM-Assisted Patching
Chengyan Ma, Jieke Shi, Ruidong Han et al. (+4 more)
Trusted Execution Environments (TEEs) provide hardware-based isolation to protect sensitive data and computations from potentially compromised operating systems (OS). However, TEE applications inevitably interact with the untrusted OS through SDK interfaces, and improper partitioning can introduce severe vulnerabilities such as data leakage and code injection. While prior work has proposed static analysis tools to detect such issues, automated repair remains largely unexplored. This problem is particularly challenging due to three TEE-specific factors: the lack of standardized secure development guidelines, the difficulty of extracting semantic information from low-level C code, and the absence of mature testing and validation methods. In this work, we present TEERepair, a framework for automatically repairing bad partitioning issues in TEE applications. Our approach tackles the above challenges by introducing a domain-specific
language (DSL) to encode repair rules that express and capture common TEE security patterns, which are instantiated as patch templates with placeholders for context-specific variables. We then leverage large
language models (LLMs) to reason about code semantics and synthesize context-aware patches, and further generate test clients to validate the repairs. We evaluate TEERepair on the TEE Partitioning Errors
Benchmark (PartitioningE-Bench), achieving a significantly higher repair success rate of 87.6% compared to baselines. Furthermore, applying TEERepair to real-world TEE projects, we submitted 5 repair pull requests, 2 of which have been confirmed and merged by project maintainers.
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All authors Chengyan Ma, Jieke Shi, Ruidong Han, Ye Liu, Feng Li, Yuqing Niu, David Lo
Cryptography and Security
Safeguarding Text-to-Image Generative Models Against Unauthorized Knowledge Distillation
Yilan Gao, Sida Huang, Hongyuan Zhang et al. (+1 more)
Closed-weight generative services are increasingly deployed through query-based APIs, where users can obtain generated outputs while model parameters remain inaccessible. However, such deployment does not prevent model stealing: an attacker can repeatedly query the service, collect large volumes of released synthetic images, and use them as training data for a private substitute model. This query-output-driven process enables unauthorized knowledge
distillation and capability replication without direct access to the original weights. To mitigate this threat, a practical defense should preserve the visual fidelity of released images, provide explicit control over perturbation magnitude, and scale efficiently to large-volume output release. We present WaveGuard, a single-pass, generator-based protection framework that safeguards released synthetic images under a user-specified perturbation budget. WaveGuard employs a frequency-aware perturbation generator to inject structured, imperceptible perturbations that maintain perceptual utility for benign viewers while reducing the usefulness of protected images as training data for unauthorized student models. Extensive experiments under WikiArt-related synthetic-output
distillation settings show that WaveGuard achieves a favorable efficacy–fidelity–efficiency trade-off, with explicit imperceptibility control and substantial gains in protection efficiency.
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All authors Yilan Gao, Sida Huang, Hongyuan Zhang, Xuelong Li
Cryptography and Security · Cross-listed from cs.SE
Finding Missing Input Validation in TEEs via LLM-Assisted Symbolic Execution
Chengyan Ma, Jieke Shi, Ruidong Han et al. (+3 more)
Trusted Execution Environments (TEEs) provide hardware-enforced isolation that protects sensitive code and data from untrusted software. Despite their strong security guarantees, analyzing TEE applications remains challenging due to the high cost and complexity of configuring complete TEE build and runtime environments, as well as the limited observability imposed by hardware isolation. This paper presents SymTEE, a novel large
language model (LLM)-assisted symbolic execution framework for detecting missing input validation issues in TEE applications without requiring real TEE setups. SymTEE begins by leveraging Abstract Syntax Tree (AST) analysis to extract TEE code slices that may lack sufficient input validation, and then employs an LLM (GPT-5 in our case) to automatically convert the extracted slices into KLEE-compatible harness programs containing lightweight mock execution environments for symbolic analysis. Evaluations on 26 vulnerabilities (11 real-world and 15 synthetic) show that SymTEE achieves 100% precision and 92.3% recall in detecting missing input validation vulnerabilities while incurring an average analysis cost of only $0.05. These results demonstrate the effectiveness and practicality of SymTEE's pioneering paradigm of LLM-assisted symbolic execution, where LLMs autonomously generate mock environments to enable automated security analysis without complex setup, providing a more accessible and scalable framework for trusted computing systems.
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All authors Chengyan Ma, Jieke Shi, Ruidong Han, Ye Liu, Yuqing Niu, David Lo
Cryptography and Security
RADAR: Defending RAG Dynamically against Retrieval Corruption
Ziyuan Chen, Yueming Lyu, Yi Liu et al. (+4 more)
While RAG systems are increasingly deployed in dynamic web search, temporal
volatility amplifies their vulnerability to
adversarial attacks. Existing static-oriented defenses struggle to handle evolving threats and incur prohibitive storage costs in dynamic settings. We propose RADAR, a framework that models reliable context selection as a graph-based energy minimization problem, solved exactly via Max-Flow Min-Cut. By incorporating a
Bayesian memory node, RADAR recursively updates a belief state instead of archiving raw historical documents, effectively balancing stability against attacks with adaptability to genuine knowledge shifts. Experiments on a novel dynamic
dataset show that RADAR achieves superior robustness and response quality with minimal storage overhead compared to the baselines.
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All authors Ziyuan Chen, Yueming Lyu, Yi Liu, Weixiang Han, Jing Dong, Caifeng Shan, Tieniu Tan
Cryptography and Security · Cross-listed from cs.DC
Secure and Parallel Determinant Computation for Large-Scale Matrices in Edge Environments
Prajwal Panth
The advent of edge computing has enabled resource-constrained clients to delegate intensive computational tasks to distributed edge servers, especially within Internet of Things (IoT) environments. Among such tasks,
Matrix Determinant Computation (MDC) remains critical for applications in control systems, cryptography, and machine learning. However, the cubic complexity of traditional determinant
algorithms makes them unsuitable for real-time processing in constrained edge scenarios. We propose a Secure Parallel Determinant Computation (SPDC) framework, which provides strong security guaranties, including
privacy-preserving MDC, across N distributed edge servers. The framework achieves
privacy through Composite Element Distortion (CED) - a lightweight encryption method that combines Element-wise Obfuscation (EWO) and the Panth Rotation
Theorem (PRT) to conceal both structural and numerical
matrix content while preserving determinant properties. Parallel LU decomposition is used to distribute encrypted
matrix blocks across an arbitrary number of untrusted edge servers, enabling efficient and scalable determinant computation. A one-way communication model further reduces coordination overhead by eliminating inter-server interactions. To ensure result integrity with minimal client burden, we further introduce two verification
algorithms: Q_2, a probabilistic scalar method, and Q_3, a deterministic and low-complexity alternative. Mathematical analysis demonstrates that the proposed framework provides strong
privacy and security guaranties, low computational overhead, and deployment flexibility - making it well-suited for secure, scalable, and real-time MDC in distributed edge-assisted systems.
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Cryptography and Security
Parser-Free Querying of Security Logs
Evan Luo, Julien Piet and David Wagner
Security analysts routinely query system logs to detect threats and investigate incidents, but each log source uses its own semi-structured format: logs are cheap to produce, but expensive to use. The standard approach, building per-source parsers to normalize logs into structured schemas, is powerful but requires continuous engineering effort for each new format. Querying raw logs directly with tools like grep avoids this cost, but requires analysts to know each source's message variants and cannot express the multi-line temporal queries that security investigations demand. We present Sieve, a system that generates executable query code from natural-
language security questions by grounding a large
language model with lightweight, automatically extracted log-format context, requiring only one LLM call per query followed by deterministic execution. Evaluating 133 security queries across 5 log types, we find that Sieve achieves over a 3x reduction in error rate on complex temporal and cross-event queries compared to manual analyst scripting, with the largest gains on the multi-line correlation tasks most critical to active investigations. Our results and
benchmark provide evidence that LLM-generated code can bridge the gap between the expressiveness of structured log querying and the immediacy of working directly with raw files.
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Cryptography and Security
Blind Spots in the Guard: How Domain-Camouflaged Injection Attacks Evade Detection in Multi-Agent LLM Systems
Aaditya Pai
Injection detectors deployed to protect LLM
agents are calibrated on static, template-based payloads that announce themselves as override directives. We identify a systematic blind spot: when payloads are generated to mimic the domain vocabulary and authority structures of the target document, what we call domain camouflaged injection, standard detectors fail to flag them, with detection rates dropping from 93.8% to 9.7% on Llama 3.1 8B and from 100% to 55.6% on Gemini 2.0 Flash. We formalize this as the Camouflage Detection Gap (CDG), the difference in injection detection rate between static and camouflaged payloads. Across 45 tasks spanning three domains and two model families, CDG is large and statistically significant (chi^2 = 38.03, p < 0.001 for Llama; chi^2 = 17.05, p < 0.001 for Gemini), with zero reverse discordant pairs in either case. We additionally evaluate Llama Guard 3, a production safety classifier, which detects zero camouflage payloads (IDRcamouflage = 0.000), confirming that the blind spot extends beyond few-shot detectors to dedicated safety classifiers. We further show that multi-
agent debate architectures amplify static injection attacks by up to 9.9x on smaller models, while stronger models show collective resistance. Targeted detector augmentation provides only partial remediation (10.2% improvement on Llama, 78.7% on Gemini), suggesting the vulnerability is architectural rather than incidental for weaker models. Our framework, task bank, and payload generator are released publicly.
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Cryptography and Security · Cross-listed from cs.LG
Optimal Guarantees for Auditing Rényi Differentially Private Machine Learning
Benjamin D. Kim, Lav R. Varshney and Daniel Alabi
We study black-box
auditing for machine learning
algorithms that claim R \ 'enyi differential
privacy (RDP) guarantees. We introduce an
auditing framework, based on hypothesis testing, that directly estimates Rényi divergence between neighboring executions using the Donsker-Varadhan (DV) variational
estimator. Our analysis yields explicit and non-asymptotic confidence intervals for RDP
auditing via class-restricted DV
estimators, separating statistical estimation error from algorithmic
privacy leakage. We prove matching minimax lower bounds showing that, up to logarithmic factors, our sample-complexity guarantees are information-theoretically optimal, thereby establishing the first optimal guarantees for
auditing RDP via DV
estimators. Empirically, we instantiate our framework for
auditing DP-SGD in a fully black-box setting. Across MNIST and CIFAR-10, and over a wide range of
privacy regimes, our auditors produce a strong overall improvement on empirical RDP lower bounds compared to prior state-of-the-art black-box methods especially at small and moderate Rényi orders where accurate
auditing is most challenging.
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