Cryptography and Security · Cross-listed from cs.LG
MedFedPure: A Medical Federated Framework with MAE-based Detection and Diffusion Purification for Inference-Time Attacks
Mohammad Karami, Mohammad Reza Nemati, Aidin Kazemi et al. (+3 more)
Artificial intelligence (AI) has shown great potential in medical imaging, particularly for
brain tumor detection using
Magnetic Resonance Imaging (MRI). However, the models remain vulnerable at inference time when they are trained collaboratively through
Federated Learning (FL), an approach adopted to protect patient
privacy.
Adversarial attacks can subtly alter medical scans in ways invisible to the human eye yet powerful enough to mislead AI models, potentially causing serious misdiagnoses. Existing defenses often assume centralized data and struggle to cope with the decentralized and diverse nature of
federated medical settings. In this work, we present MedFedPure, a personalized
federated learning defense framework designed to protect diagnostic AI models at inference time without compromising
privacy or accuracy. MedFedPure combines three key elements: (1) a personalized FL model that adapts to the unique data distribution of each institution; (2) a Masked Autoencoder (MAE) that detects suspicious inputs by exposing hidden perturbations; and (3) an adaptive
diffusion-based purification module that selectively cleans only the flagged scans before classification. Together, these steps offer robust protection while preserving the integrity of normal, benign images. We evaluated MedFedPure on the Br35H
brain MRI
dataset. The results show a significant gain in
adversarial robustness, improving performance from 49.50% to 87.33% under strong attacks, while maintaining a high clean accuracy of 97.67%. By operating locally and in real time during diagnosis, our framework provides a practical path to deploying secure, trustworthy, and
privacy-preserving AI tools in clinical workflows. Index Terms: cancer, tumor detection,
federated learning, masked autoencoder,
diffusion,
privacy
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All authors Mohammad Karami, Mohammad Reza Nemati, Aidin Kazemi, Ali Mikaeili Barzili, Hamid Azadegan, Behzad Moshiri
Cryptography and Security · Cross-listed from cs.CY
Preserving security in a world with powerful AI Considerations for the future Defense Architecture
Nicholas Generous, Brian Cook and Jason Pruet
Advances in AI threaten to invalidate assumptions underpinning today's defense architecture. We argue that the current U.S. defense program of record, designed in an era before capable machine intelligence, cannot by itself preserve national security against rapidly emerging AI enabled threats. Instead, shoring up legacy systems must be coupled with entirely new elements of a defense architecture. We outline immediate steps to adapt the Department of Energy National
Nuclear Security Administration National Laboratories to ensure agility and resilience in an era of powerful AI.
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Cryptography and Security
ConVerse: Benchmarking Contextual Safety in Agent-to-Agent Conversations
Amr Gomaa, Ahmed Salem and Sahar Abdelnabi
As
language models evolve into autonomous
agents that act and communicate on behalf of users, ensuring safety in multi-
agent ecosystems becomes a central challenge. Interactions between personal assistants and external service providers expose a core tension between utility and protection: effective collaboration requires information sharing, yet every exchange creates new attack surfaces. We introduce ConVerse, a dynamic
benchmark for evaluating
privacy and security risks in
agent-
agent interactions. ConVerse spans three practical domains (travel, real estate, insurance) with 12 user personas and over 864 contextually grounded attacks (611
privacy, 253 security). Unlike prior single-
agent settings, it models autonomous, multi-turn
agent-to-
agent conversations where malicious requests are embedded within plausible discourse.
Privacy is tested through a three-tier taxonomy assessing abstraction quality, while security attacks target tool use and preference manipulation. Evaluating seven state-of-the-art models reveals persistent vulnerabilities;
privacy attacks succeed in up to 88% of cases and security breaches in up to 60%, with stronger models leaking more. By unifying
privacy and security within interactive multi-
agent contexts, ConVerse reframes safety as an emergent property of communication.
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Cryptography and Security · Cross-listed from cs.CV
$\mathbf{S^2LM}$: Towards Semantic Steganography via Large Language Models
Huanqi Wu, Huangbiao Xu, Yongliang Xu et al. (+3 more)
Despite remarkable progress in steganography,
embedding sentence-level information into cover media remains challenging. In this work, we present the concept of Semantic-Payload Steganography, which aims to hide semantically meaningful and structured content, such as sentences, in cover media. Based on this concept, we present Sentence-to-Image Steganography as an instance that enables the hiding of sentence-level messages within a cover image. To accomplish this feat, we propose Semantic-Payload Steganographic
Language Model ($\mathbf{S^2LM}$), which leverages large
language models to embed high-level textual information into images. $\mathbf{S^2LM}$ redesigns the entire pipeline, involving the LLM throughout the process to enable the hiding and recovery of sentences. To evaluate semantic-payload steganography methods, we establish a
benchmark named Invisible Text (IVT), comprising a diverse set of corpus as secret messages. Experimental results demonstrate that $\mathbf{S^2LM}$ effectively recovers natural-
language messages while maintaining high visual quality. The source code will be released at https://github.com/aoli-gei/S2LM.
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All authors Huanqi Wu, Huangbiao Xu, Yongliang Xu, Jiaxin Cai, Xiao Ke, Hang Cheng
Cryptography and Security · Cross-listed from quant-ph
Optimization of Information Reconciliation for Decoy-State Quantum Key Distribution over a Satellite Downlink Channel
Thomas Scarinzi, Davide Orsucci, Marco Ferrari et al. (+1 more)
Quantum key distribution (QKD) is a cryptographic solution that leverages the properties of
quantum mechanics to be resistant and secure even against an attacker with unlimited computational power. Satellite-based links are important in QKD because they can reach distances that the best fiber systems cannot. However, links between satellites in low Earth orbit (LEO) and ground stations have a duration of only a few minutes, resulting in the generation of a small amount of secure keys. In this context, we investigate the optimization of the information reconciliation step of the QKD post-processing in order to generate as much secure key as possible. As a first step, we build an accurate model of the downlink signal and
quantum bit error rate (QBER) during a complete satellite pass, which are time-varying due to three effects: (i) the varying link geometry over time, (ii) the scintillation effect, and (iii) the different signal intensities adopted in the Decoy-State protocol. Leveraging the a-priori information on the instantaneous QBER, we improve the efficiency of information reconciliation (IR) (i.e., the error correction phase) in the Decoy-State BB84 protocol, resulting in a secure key that is almost 3% longer for realistic scenarios.
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All authors Thomas Scarinzi, Davide Orsucci, Marco Ferrari, Luca Barletta
Cryptography and Security
BLADE: Behavior-Level Anomaly Detection Using Network Traffic in Web Services
Zhibo Dong, Yong Huang, Shubao Sun et al. (+2 more)
With their widespread popularity, web services have become the main targets of various cyberattacks. Existing traffic anomaly detection approaches focus on flow-level attacks, yet fail to recognize behavior-level attacks, which appear benign in individual flows but reveal malicious purpose using multiple network flows. To transcend this limitation, we propose a novel unsupervised traffic anomaly detection system, BLADE, capable of detecting not only flow-level but also behavior-level attacks in web services. Our key observation is that application-layer operations of web services exhibit distinctive communication patterns at the network layer from a multi-flow perspective. BLADE first exploits a flow autoencoder to learn a latent feature representation and calculates its reconstruction losses per flow. Then, the latent representation is assigned a pseudo operation label using an unsupervised clustering method. Next, an anomaly score is computed based on the reconstruction losses. Finally, the triplets of timestamps, pseudo labels, and anomaly scores from multiple flows are aggregated and fed into a one-class classifier to characterize the behavior patterns of legitimate web operations, enabling the detection of flow-level and behavior-level anomalies. BLADE is extensively evaluated on both the custom
dataset and the CIC-IDS2017
dataset. The experimental results demonstrate BLADE's superior performance, achieving high F1 scores of 0.9732 and 0.9801, respectively, on the two
datasets, and outperforming traditional single-flow anomaly detection baselines.
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All authors Zhibo Dong, Yong Huang, Shubao Sun, Wentao Cui, Zhihua Wang
Cryptography and Security · Cross-listed from cs.RO
Procedimiento de auditoría de ciberseguridad para sistemas autónomos: metodología, amenazas y mitigaciones
Adrián Campazas-Vega, Claudia Álvarez-Aparicio, David Sobrín-Hidalgo et al. (+4 more)
The deployment of autonomous systems has experienced remarkable growth in recent years, driven by their integration into sectors such as industry, medicine, logistics, and domestic environments. This expansion is accompanied by a series of security issues that entail significant risks due to the critical nature of autonomous systems, especially those operating in human-interaction environments. Furthermore, technological advancement and the high operational and architectural complexity of autonomous systems have resulted in an increased attack surface. This article presents a specific security
auditing procedure for autonomous systems, based on a layer-structured methodology, a threat taxonomy adapted to the robotic context, and a set of concrete mitigation measures. The validity of the proposed approach is demonstrated through four practical case studies applied to representative robotic platforms: the
Vision 60 military quadruped from Ghost Robotics, the A1
robot from Unitree Robotics, the UR3 collaborative arm from Universal
Robots, and the Pepper social
robot from Aldebaran Robotics.
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All authors Adrián Campazas-Vega, Claudia Álvarez-Aparicio, David Sobrín-Hidalgo, Laura Inyesto-Alonso, Francisco Javier Rodríguez-Lera, Vicente Matellán-Olivera, Ángel Manuel Guerrero-Higueras
Cryptography and Security
SmartSecChain-SDN: A Blockchain-Integrated Intelligent Framework for Secure and Efficient Software-Defined Networks
Azhar Hussain Mozumder, M. John Basha and Chayapathi A. R
With more and more existing networks being transformed to Software-Defined Networking (SDN), they need to be more secure and demand smarter ways of traffic control. This work, SmartSecChain-SDN, is a platform that combines machine learning based intrusion detection, blockchain-based storage of logs, and application-awareness-based priority in SDN networks. To detect network intrusions in a real-time, precision and low-false positives setup, the framework utilizes the application of advanced machine learning
algorithms, namely Random Forest, XGBoost, CatBoost, and CNN-BiLSTM. SmartSecChain-SDN is based on the Hyperledger Fabric, which is a permissioned blockchain technology, to provide secure, scalable, and
privacy-preserving storage and, thus, guarantee that the Intrusion Detection System (IDS) records cannot be altered and can be analyzed comprehensively. The system also has Quality of Service (QoS) rules and traffic shaping based on applications, which enables prioritization of critical services, such as VoIP,
video conferencing, and business applications, as well as de-prioritization of non-essential traffic, such as downloads and updates. Mininet can simulate real-time SDN scenarios because it is used to prototype whole architectures. It is also compatible with controllers OpenDaylight and Ryu. It has tested the framework using the InSDN
dataset and proved that it can identify different kinds of cyberattacks and handle bandwidth allocation efficiently under circumstances of resource constraints. SmartSecChain-SDN comprehensively addresses SDN system protection, securing and enhancing. The proposed study offers an innovative, extensible way to improve cybersecurity, regulatory compliance, and the administration of next-generation programmable networks.
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Cryptography and Security
A Secured Intent-Based Networking (sIBN) with Data-Driven Time-Aware Intrusion Detection
Urslla Uchechi Izuazu, Mounir Bensalem and Admela Jukan
While Intent-Based Networking (IBN) promises operational efficiency through autonomous and abstraction-driven network management, a critical unaddressed issue lies in IBN's implicit trust in the integrity of intent ingested by the network. This inherent assumption of data reliability creates a blind spot exploitable by Man-in-the-Middle (MitM) attacks, where an adversary intercepts and alters intent before it is enacted, compelling the network to orchestrate malicious configurations. This study proposes a secured IBN (sIBN) system with data driven intrusion detection method designed to secure legitimate user intent from
adversarial tampering. The proposed intent intrusion detection system uses a ML model applied for network behavioral anomaly detection to reveal temporal patterns of intent tampering. This is achieved by leveraging a set of original behavioral metrics and newly engineered time-aware features, with the model's hyperparameters fine-tuned through the randomized search cross-validation (RSCV) technique. Numerical results based on real-world data sets, show the effectiveness of sIBN, achieving the best performance across standard evaluation metrics, in both binary and multi classification tasks, while maintaining low error rates.
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Cryptography and Security
Cybersecurity AI in OT: Insights from an AI Top-10 Ranker in the Dragos OT CTF 2025
Víctor Mayoral-Vilches, Luis Javier Navarrete-Lozano, Francesco Balassone et al. (+3 more)
Operational Technology (OT) cybersecurity increasingly relies on rapid response across malware analysis, network forensics, and reverse engineering disciplines. We examine the performance of Cybersecurity AI (CAI), powered by the alias1 model, during the Dragos OT CTF 2025 – a 48-hour industrial control system (ICS) competition with more than 1,000 teams. Using CAI telemetry and official leaderboard data, we quantify CAI's trajectory relative to the leading human-operated teams. CAI reached Rank~1 between competition hours 7.0 and 8.0, crossed 10,000 points at 5.42~hours (1,846~pts/h), and completed 32 of the competition's 34 challenges before automated operations were paused at hour~24 with a final score of 18,900 points (6th place). The top-3 human teams solved 33 of 34 challenges, collectively leaving only the 600-point “Kiddy Tags – 1” unsolved; they were also the only teams to clear the 1,000-point “Moot Force” binary. The top-5 human teams averaged 1,347~pts/h to the same milestone, marking a 37% velocity advantage for CAI. We analyse time-resolved scoring, category coverage, and solve cadence. The evidence indicates that a mission-configured AI
agent can match or exceed expert human crews in early-phase OT incident response while remaining subject to practical limits in sustained, multi-day operations.
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All authors Víctor Mayoral-Vilches, Luis Javier Navarrete-Lozano, Francesco Balassone, María Sanz-Gómez, Cristóbal Ricardo Veas Chávez, Maite del Mundo de Torres
Cryptography and Security
Confidentiality in a Card-Based Protocol Under Repeated Biased Shuffles
Do Hyun Kim and Ahmet Cetinkaya
In this paper, we provide a probabilistic analysis of the confidentiality in a card-based protocol. We focus on Bert den Boer's original Five Card Trick to develop our approach. Five Card Trick was formulated as a secure two-party computation method, where two players use colored cards with identical backs to calculate the logical AND operation on the bits that they choose. In this method, the players first arrange the cards privately, and then shuffle them through a random cut. Finally, they reveal the shuffled arrangement to determine the result of the operation. An unbiased random cut is essential to prevent players from exposing their chosen bits to each other. However, players typically choose to move cards within the deck even though not moving any cards should be equally likely. This unconscious behavior results in a biased, nonuniform shuffling-distribution in the sense that some arrangements of cards are slightly more probable after the cut. Such a nonuniform distribution creates an opportunity for a malicious player to gain advantage in guessing the other player's choice. We provide the conditional probabilities of such guesses as a way to quantify the information leakage. Furthermore, we utilize the eigenstructure of a Markov chain to derive tight bounds on the number of times the biased random cuts must be repeated to reduce the leakage to an acceptable level. We also discuss the generalization of our approach to the setting where shuffling is conducted by a malicious player.
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Cryptography and Security
PhantomFetch: Obfuscating Loads against Prefetcher Side-Channel Attacks
Xingzhi Zhang, Buyi Lv, Yimin Lu et al. (+1 more)
The IP-stride prefetcher has recently been exploited to leak secrets through side-channel attacks. It, however, cannot be simply disabled for security with prefetching speedup as a sacrifice. The state-of-the-art defense tries to retain the prefetching effect by hardware modification. In this paper, we present PhantomFetch as the first prefetching-retentive and hardware-agnostic defense. It avoids potential remanufacturing cost and enriches applicability to off-the-shelf devices. The key idea is to directly break the exploitable coupling between trained prefetcher entries and the victim's secret-dependent loads by obfuscating the sensitive load effects of the victim. The experiment results show that PhantomFetch can secure the IP-stride prefetcher with only negligible overhead.
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All authors Xingzhi Zhang, Buyi Lv, Yimin Lu, Kai Bu
Cryptography and Security
Quantifying the Risk of Transferred Black Box Attacks
Disesdi Susanna Cox and Niklas Bunzel
Neural networks have become pervasive across various applications, including security-related products. However, their widespread adoption has heightened concerns regarding vulnerability to
adversarial attacks. With emerging regulations and standards emphasizing security, organizations must reliably quantify risks associated with these attacks, particularly regarding transferred
adversarial attacks, which remain challenging to evaluate accurately. This paper investigates the complexities involved in resilience testing against transferred
adversarial attacks. Our analysis specifically addresses black-box evasion attacks, highlighting transfer-based attacks due to their practical significance and typically high transferability between neural network models. We underline the computational infeasibility of exhaustively exploring high-dimensional input spaces to achieve complete test coverage. As a result, comprehensive
adversarial risk mapping is deemed impractical. To mitigate this limitation, we propose a targeted resilience testing framework that employs surrogate models strategically selected based on Centered Kernel
Alignment (CKA) similarity. By leveraging surrogate models exhibiting both high and low CKA similarities relative to the target model, the proposed approach seeks to optimize coverage of
adversarial subspaces. Risk estimation is conducted using regression-based
estimators, providing organizations with realistic and actionable risk quantification.
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Cryptography and Security
TRICK: Time and Range Integrity ChecK using Low Earth Orbiting Satellite for Securing GNSS
Arslan Mumtaz and Mridula Singh
Global
Navigation Satellite Systems (GNSS) provide Positioning,
Navigation, and Timing (PNT) information to over 4 billion devices worldwide. Despite its pervasive use in safety critical and high precision applications, GNSS remains vulnerable to spoofing attacks. Cryptographic enhancements, such as the use of TESLA protocol in Galileo, to provide
navigation message authentication do not mitigate time of arrival manipulations. In this paper, we propose TRICK, a primitive for secure positioning that closes this gap by introducing a fundamentally new approach that only requires two way communications with a single reference node along with multiple broadcast signals. Unlike classical Verifiable Multilateration (VM), which requires establishing two way communication with each reference nodes, our solution relies on only two measurements with a trusted Low Earth Orbiting (LEO) satellite and combines broadcast
navigation signals. We rigorously prove that combining the LEO satellite based two way range measurements and multiple one way ranges such as from broadcast signals of GNSS into ellipsoidal constraint restores the same guarantees as offered by VM whilst using minimal infrastructure and message exchanges. Through detailed analysis, we show that our approach reliably detects spoofing attempts while adding negligible computation overhead.
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Cryptography and Security
Did You Forkget It? Detecting One-Day Vulnerabilities in Open-source ForksWith Global History Analysis
Romain Lefeuvre, Charly Reux, Stefano Zacchiroli et al. (+2 more)
Tracking vulnerabilities inherited from third-party open-source software is a well-known challenge, often addressed by tracing the threads of dependency information. However, vulnerabilities can also propagate through forking: a code repository forked after the introduction of a vulnerability, but before it is patched, may remain vulnerable long after the vulnerability has been fixed in the initial repository. History analysis approaches are used to track vulnerable software versions at scale. However, such approaches fail to track vulnerabilities in forks, leaving fork maintainers to identify them manually. This paper presents a global history analysis approach to help software developers identify one-day (known but unpatched) vulnerabilities in forked repositories. Leveraging the global graph of public code, as captured by the Software Heritage archive, our approach propagates vulnerability information at the commit level and performs automated impact analysis. Starting from 7162 repositories with vulnerable commits listed in OSV, we propagate vulnerability information to 2.2 million forks. We evaluate our approach by filtering forks with significant user bases whose latest commit is still potentially vulnerable, manually
auditing the code, and contacting maintainers for confirmation and responsible disclosure. This process identified 135 high-severity one-day vulnerabilities, achieving a precision of 0.69, with 9 confirmed by maintainers.
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All authors Romain Lefeuvre, Charly Reux, Stefano Zacchiroli, Olivier Barais, Benoit Combemale
Cryptography and Security
The Future of Fully Homomorphic Encryption System: from a Storage I/O Perspective
Lei Chen, Erci Xu, Yiming Sun et al. (+8 more)
Fully Homomorphic Encryption (FHE) allows computations to be performed on encrypted data, significantly enhancing user
privacy. However, the I/O challenges associated with deploying FHE applications remains understudied. We analyze the impact of storage I/O on the performance of FHE applications and summarize key lessons from the status quo. Key results include that storage I/O can degrade the performance of ASICs by as much as 357$\times$ and reduce GPUs performance by up to 22$\times$.
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All authors Lei Chen, Erci Xu, Yiming Sun, Shengyu Fan, Xianglong Deng, Guiming Shi, Guang Fan, Liang Kong, Yilan Zhu, Shoumeng Yan, Mingzhe Zhang
Cryptography and Security
Zero Trust Security Model Implementation in Microservices Architectures Using Identity Federation
Rethish Nair Rajendran, Sathish Krishna Anumula, Dileep Kumar Rai et al. (+1 more)
The microservice bombshells that have been linked with the microservice expansion have altered the application architectures, offered agility and scalability in terms of complexity in security trade-offs. Feeble legacy-based perimeter-based policies are unable to offer safeguard to distributed workloads and temporary interaction among and in between the services. The article itself is a case on the need of the Zero Trust Security Model of micro services ecosystem, particularly, the fact that human and workloads require identity federation. It is proposed that the solution framework will be based on industry-standard authentication and authorization and end-to-end trust identity technologies, including Authorization and OpenID connect (OIDC), Authorization and OAuth 2.0
token exchange, and Authorization and SPIFFE/ SPIRE workload identities. Experimental evaluation is a unique demonstration of a superior security position of making use of a smaller attack surface, harmony policy enforcement, as well as interoperability across multi- domain environments. The research results overlay that the
federated identity combined with the Zero Trust basics not only guarantee the rules relating to authentication and authorization but also fully complies with the latest DevSecOps standards of microservice deployment, which is automated, scaled, and resilient. The current project offers a stringent roadmap to the organizations that desire to apply Zero Trust in cloud-native technologies but will as well guarantee adherence and interoperability.
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All authors Rethish Nair Rajendran, Sathish Krishna Anumula, Dileep Kumar Rai, Sachin Agrawal