Cryptography and Security · Cross-listed from cs.CV
Noise Aggregation Analysis Driven by Small-Noise Injection: Efficient Membership Inference for Diffusion Models
Guo Li, Weihong Chen and Yongfu Fan
Diffusion models have demonstrated powerful performance in generating high-quality images. A typical example is text-to-image generator like Stable
Diffusion. However, their widespread use also poses potential
privacy risks. A key concern is membership inference attacks, which attempt to determine whether a particular data sample was used in the model training process. Existing membership inference attacks against
diffusion models either directly exploit sample loss differences or rely on image-level reconstruction differences. Both approaches commonly ignore the consistency characteristics of noise prediction during the
diffusion process, resulting in either low inference accuracy or high computational costs. To address these shortcomings, we propose a membership inference method based on noise aggregation analysis, and introduce a single-step, low-intensity noise injection
diffusion strategy to amplify differences between member and non-member samples. Our proposed approach substantially reduces model query requirements while delivering more efficient and accurate membership inference.
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Cryptography and Security
When Intelligence Fails: An Empirical Study on Why LLMs Struggle with Password Cracking
Mohammad Abdul Rehman, Syed Imad Ali Shah, Abbas Anwar et al. (+2 more)
The remarkable capabilities of Large
Language Models (LLMs) in natural
language understanding and generation have sparked interest in their potential for cybersecurity applications, including password guessing. In this study, we conduct an empirical investigation into the efficacy of pre-trained LLMs for password cracking using synthetic user profiles. Specifically, we evaluate the performance of state-of-the-art open-source LLMs such as TinyLLaMA, Falcon-RW-1B, and Flan-T5 by prompting them to generate plausible passwords based on structured user attributes (e.g., name, birthdate, hobbies). Our results, measured using Hit@1, Hit@5, and Hit@10 metrics under both plaintext and SHA-256 hash comparisons, reveal consistently poor performance, with all models achieving less than 1.5% accuracy at Hit@10. In contrast, traditional rule-based and combinator-based cracking methods demonstrate significantly higher success rates. Through detailed analysis and visualization, we identify key limitations in the generative
reasoning of LLMs when applied to the domain-specific task of password guessing. Our findings suggest that, despite their linguistic prowess, current LLMs lack the domain adaptation and memorization capabilities required for effective password inference, especially in the absence of supervised fine-tuning on leaked password
datasets. This study provides critical insights into the limitations of LLMs in
adversarial contexts and lays the groundwork for future efforts in secure,
privacy-preserving, and robust password modeling.
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All authors Mohammad Abdul Rehman, Syed Imad Ali Shah, Abbas Anwar, Noor Islam, Hamid Khan
Cryptography and Security
From Flows to Words: Can Zero-/Few-Shot LLMs Detect Network Intrusions? A Grammar-Constrained, Calibrated Evaluation on UNSW-NB15
Mohammad Abdul Rehman, Syed Imad Ali Shah, Abbas Anwar et al. (+1 more)
Large
Language Models (LLMs) can reason over natural-
language inputs, but their role in intrusion detection without fine-tuning remains uncertain. This study evaluates a
prompt-only approach on UNSW-NB15 by converting each network flow to a compact textual record and augmenting it with lightweight, domain-inspired boolean flags (asymmetry, burst rate, TTL irregularities, timer anomalies, rare service/state, short bursts). To reduce output drift and support measurement, the model is constrained to produce structured, grammar-valid responses, and a single decision threshold is calibrated on a small development split. We compare zero-shot, instruction-guided, and few-shot prompting to strong tabular and neural baselines under identical splits, reporting accuracy, precision, recall, F1, and macro scores. Empirically, unguided prompting is unreliable, while instructions plus flags substantially improve detection quality; adding calibrated scoring further stabilizes results. On a balanced subset of two hundred flows, a 7B instruction-tuned model with flags reaches macro-F1 near 0.78; a lighter 3B model with few-shot cues and calibration attains F1 near 0.68 on one thousand examples. As the evaluation set grows to two thousand flows, decision quality decreases, revealing sensitivity to coverage and prompting. Tabular baselines remain more stable and faster, yet the
prompt-only pipeline requires no gradient training, produces readable artifacts, and adapts easily through instructions and flags. Contributions include a flow-to-text protocol with interpretable cues, a calibration method for thresholding, a systematic baseline comparison, and a reproducibility bundle with
prompts, grammar, metrics, and figures.
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All authors Mohammad Abdul Rehman, Syed Imad Ali Shah, Abbas Anwar, Noor Islam
Cryptography and Security
A Versatile Framework for Designing Group-Sparse Adversarial Attacks
Alireza Heshmati, Saman Soleimani Roudi, Sajjad Amini et al. (+2 more)
Existing
adversarial attacks often neglect perturbation sparsity, limiting their ability to model structural changes and to explain how deep neural networks (DNNs) process meaningful input patterns. We propose ATOS (Attack Through Overlapping Sparsity), a differentiable optimization framework that generates structured, sparse
adversarial perturbations in element-wise, pixel-wise, and group-wise forms. For white-box attacks on image classifiers, we introduce the Overlapping Smoothed L0 (OSL0) function, which promotes convergence to a stationary point while encouraging sparse, structured perturbations. By grouping channels and adjacent pixels, ATOS improves interpretability and helps identify robust versus non-robust features. We approximate the L-infinity gradient using the logarithm of the sum of exponential absolute values to tightly control perturbation magnitude. On CIFAR-10 and ImageNet, ATOS achieves a 100% attack success rate while producing significantly sparser and more structurally coherent perturbations than prior methods. The structured group-wise attack highlights critical regions from the network's perspective, providing counterfactual explanations by replacing class-defining regions with robust features from the target class.
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All authors Alireza Heshmati, Saman Soleimani Roudi, Sajjad Amini, Shahrokh Ghaemmaghami, Farokh Marvasti
Cryptography and Security · Cross-listed from cs.IT
Feedback Lunch: Learned Feedback Codes for Secure Communications
Yingyao Zhou, Natasha Devroye and Onur Günlü
We consider reversely-degraded secure-communication channels, for which the secrecy capacity is zero if there is no channel feedback. Specifically, we focus on a seeded modular code design for the block-fading Gaussian wiretap channel with channel-output feedback, combining universal hash functions for security and learned feedback-based codes for reliability. The trade-off between communication reliability and information leakage is studied, illustrating that feedback enables agreeing on a secret key shared between legitimate parties, overcoming the security advantage of the eavesdropper. Our findings motivate code designs for sensing-assisted secure communications in the context of integrated sensing and communication (
ISAC).
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Cryptography and Security
Structuring Security: A Survey of Cybersecurity Ontologies, Semantic Log Processing, and LLMs Application
Bruno Lourenço, Pedro Adão, João F. Ferreira et al. (+2 more)
This survey investigates how ontologies, semantic log processing, and Large
Language Models (LLMs) enhance cybersecurity. Ontologies structure domain knowledge, enabling interoperability, data integration, and advanced threat analysis. Security logs, though critical, are often unstructured and complex. To address this, automated construction of Knowledge Graphs (KGs) from raw logs is emerging as a key strategy for organizing and
reasoning over security data. LLMs enrich this process by providing contextual understanding and extracting insights from unstructured content. This work aligns with European Union (EU) efforts such as NIS 2 and the Cybersecurity Taxonomy, highlighting challenges and opportunities in intelligent ontology-driven cyber defense.
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All authors Bruno Lourenço, Pedro Adão, João F. Ferreira, Mario Monteiro Marques, Cátia Vaz
Cryptography and Security
DESTinE Block: Private Blockchain Based Data Storage Framework for Power System
Khandaker Akramul Haque and Katherine R. Davis
This paper presents DESTinE Block, a blockchain-based data storage framework designed for power systems and optimized for resource-constrained environments, including grid-edge devices such as single-board computers. The proposed architecture leverages the InterPlanetary File System (IPFS) for storing large files while maintaining secure and traceable metadata on a custom blockchain named DESTinE Block. The metadata, comprising the IPFS Content Identifier (CID), uploader identity, administrator verification, and timestamp; is immutably recorded on-chain to ensure authenticity and integrity. DESTinE Block adopts a dual-blockchain abstraction, where the blockchain remains unaware of the IPFS storage layer to enhance security and limit the exposure of sensitive file data. The consensus mechanism is based on Proof of Authority (PoA), where both an administrator and an uploader with distinct cryptographic key pairs are required to create a block collaboratively. Each block contains verified signatures of both parties and is designed to be computationally efficient, enabling deployment on devices like the Raspberry Pi 5. The framework was tested on both an x86-based device and an ARM64-based Raspberry Pi, demonstrating its potential for secure, decentralized logging and measurement storage in smart grid applications. Moreover, DESTinE Block is compared with a similar framework based on Multichain. The results indicate that DESTinE Block provides a promising solution for tamper-evident data retention in distributed power system infrastructure while maintaining minimal hardware requirements.
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Cryptography and Security
Patronus: Safeguarding Text-to-Image Models against White-Box Adversaries
Xinfeng Li, Shengyuan Pang, Jialin Wu et al. (+5 more)
Text-to-image (T2I) models, though exhibiting remarkable creativity in image generation, can be exploited to produce unsafe images. Existing safety measures, e.g., content moderation or model
alignment, fail in the presence of white-box adversaries who know and can adjust model parameters, e.g., by fine-tuning. This paper presents a novel defensive framework, named Patronus, which equips T2I models with holistic protection to defend against white-box adversaries. Specifically, we design an internal moderator that decodes unsafe input features into zero vectors while ensuring the decoding performance of benign input features. Furthermore, we strengthen the model
alignment with a carefully designed non-fine-tunable learning mechanism, ensuring the T2I model will not be compromised by malicious fine-tuning. We conduct extensive experiments to validate the intactness of the performance on safe content generation and the effectiveness of rejecting unsafe content generation. Results also confirm the resilience of Patronus against various fine-tuning attacks by white-box adversaries.
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All authors Xinfeng Li, Shengyuan Pang, Jialin Wu, Jiangyi Deng, Huanlong Zhong, Yanjiao Chen, Jie Zhang, Wenyuan Xu
Cryptography and Security
A First Look at the Security Issues in the Model Context Protocol Ecosystem
Xiaofan Li and Xing Gao
The Model Context Protocol (MCP) has emerged as a standard for connecting large
language models (LLMs) with external tools. However, this MCP ecosystem introduces new security risks across hosts, servers, and registries. In this paper, we present the first cross-entity security study of MCP under a two-stage attack surface. At the registry-level, weak vetting and ownership checks allow
adversarial or hijacked servers to enter hosts. After integration, attacker-controlled tool metadata can shape LLM
reasoning and induce attacker-intended operations, which hosts execute without independent verification. Code-level vulnerabilities (e.g., code injection) are not required but can amplify attacker-controlled parameters into exploitation. We analyze 67,057 servers across six public registries and identify widespread conditions enabling server hijacking and invocation manipulation. We further implement MCPInspect, a pre-integration analysis tool that detects misleading tool metadata and exploitable code vulnerabilities, identifying 833 vulnerable servers and 18 with suspicious descriptions.
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Cryptography and Security
$\rho$Hammer: Reviving RowHammer Attacks on New Architectures via Prefetching
Weijie Chen, Shan Tang, Yulin Tang et al. (+3 more)
Rowhammer is a critical vulnerability in dynamic random access
memory (DRAM) that continues to pose a significant threat to various systems. However, we find that conventional load-based attacks are becoming highly ineffective on the most recent architectures such as Intel Alder and Raptor Lake. In this paper, we present $\rho$Hammer, a new Rowhammer framework that systematically overcomes three core challenges impeding attacks on these new architectures. First, we design an efficient and generic DRAM address mapping reverse-engineering method that uses selective pairwise measurements and structured deduction, enabling recovery of complex mappings within seconds on the latest
memory controllers. Second, to break through the activation rate bottleneck of load-based hammering, we introduce a novel prefetch-based hammering paradigm that leverages the asynchronous nature of x86 prefetch instructions and is further enhanced by multi-bank parallelism to maximize throughput. Third, recognizing that speculative execution causes more severe disorder issues for prefetching, which cannot be simply mitigated by
memory barriers, we develop a counter-speculation hammering technique using control-flow obfuscation and optimized NOP-based pseudo-barriers to maintain prefetch order with minimal overhead. Evaluations across four latest Intel architectures demonstrate $\rho$Hammer's breakthrough effectiveness: it induces up to 200K+ additional bit flips within 2-hour attack pattern fuzzing processes and has a 112x higher flip rate than the load-based hammering baselines on Comet and Rocket Lake. Also, we are the first to revive Rowhammer attacks on the latest Raptor Lake architecture, where baselines completely fail, achieving stable flip rates of 2,291/min and fast end-to-end exploitation.
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All authors Weijie Chen, Shan Tang, Yulin Tang, Xiapu Luo, Yinqian Zhang, Weizhong Qiang
Cryptography and Security
Heimdallr: Fingerprinting SD-WAN Control-Plane Architecture via Encrypted Control Traffic
Minjae Seo, Jaehan Kim, Eduard Marin et al. (+5 more)
Software-defined wide area network (SD-WAN) has emerged as a new paradigm for steering a large-scale network flexibly by adopting distributed software-defined network (SDN) controllers. The key to building a logically centralized but physically distributed control-plane is running diverse cluster management protocols to achieve consistency through an exchange of control traffic. Meanwhile, we observe that the control traffic exposes unique time-series patterns and directional relationships due to the operational structure even though the traffic is encrypted, and this pattern can disclose confidential information such as control-plane
topology and protocol dependencies, which can be exploited for severe attacks. With this insight, we propose a new SD-WAN fingerprinting system, called Heimdallr. It analyzes periodical and operational patterns of SD-WAN cluster management protocols and the context of flow directions from the collected control traffic utilizing a deep learning-based approach, so that it can classify the cluster management protocols automatically from miscellaneous control traffic
datasets. Our evaluation, which is performed in a realistic SD-WAN environment consisting of geographically distant three campus networks and one enterprise network shows that Heimdallr can classify SD-WAN control traffic with $\geq$ 93%, identify individual protocols with $\geq$ 80% macro F-1 scores, and finally can infer control-plane
topology with $\geq$ 70% similarity.
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All authors Minjae Seo, Jaehan Kim, Eduard Marin, Myoungsung You, Taejune Park, Seungsoo Lee, Seungwon Shin, Jinwoo Kim
Cryptography and Security · Cross-listed from cs.LG
Colliding with Adversaries at ECML-PKDD 2025 Adversarial Attack Competition 1st Prize Solution
Dimitris Stefanopoulos and Andreas Voskou
This report presents the winning solution for Task 1 of Colliding with Adversaries: A Challenge on Robust Learning in High Energy Physics Discovery at ECML-PKDD 2025. The task required designing an
adversarial attack against a provided classification model that maximizes misclassification while minimizing perturbations. Our approach employs a multi-round gradient-based strategy that leverages the differentiable structure of the model, augmented with random initialization and sample-mixing techniques to enhance effectiveness. The resulting attack achieved the best results in perturbation size and fooling success rate, securing first place in the competition.
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Cryptography and Security
EditMark: Watermarking Large Language Models based on Model Editing
Shuai Li, Kejiang Chen, Jun Jiang et al. (+5 more)
Large
Language Models (LLMs) have demonstrated remarkable capabilities, but their training requires extensive data and computational resources, rendering them valuable digital assets. Therefore, it is essential to watermark LLMs to protect their copyright and trace unauthorized use or resale. Existing methods for watermarking LLMs primarily rely on training LLMs with a watermarked
dataset, which entails burdensome training costs and negatively impacts the LLM's performance. In addition, their watermarked texts are not logical or natural, thereby reducing the stealthiness of the watermark. To address these issues, we propose EditMark, the first watermarking method that leverages model editing to embed a training-free, stealthy, and performance-lossless watermark for LLMs. We observe that some questions have multiple correct answers. Therefore, we assign each answer a unique watermark and update the weights of LLMs to generate corresponding questions and answers through the model editing technique. In addition, we refine the model editing technique to align with the requirements of watermark
embedding. Specifically, we introduce an adaptive multi-round stable editing strategy, coupled with the injection of a noise
matrix, to improve both the effectiveness and robustness of the watermark
embedding. Extensive experiments indicate that EditMark can embed 32-bit watermarks into LLMs within 20 seconds (Fine-tuning: 6875 seconds) with a watermark extraction success rate of 100%, which demonstrates its effectiveness and efficiency. External experiments further demonstrate that EditMark has fidelity, stealthiness, and a certain degree of robustness against common attacks.
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All authors Shuai Li, Kejiang Chen, Jun Jiang, Jie Zhang, Qiyi Yao, Kai Zeng, Weiming Zhang, Nenghai Yu
Cryptography and Security
Efficient and Privacy-Preserving Binary Dot Product via Multi-Party Computation
Fatemeh Jafarian Dehkordi, Elahe Vedadi, Alireza Feizbakhsh et al. (+2 more)
Striking a balance between protecting data
privacy and enabling collaborative computation is a critical challenge for distributed machine learning. While
privacy-preserving techniques for
federated learning have been extensively developed, methods for scenarios involving bitwise operations, such as tree-based vertical
federated learning (VFL), are still underexplored. Traditional mechanisms, including Shamir's secret sharing and multi-party computation (MPC), are not optimized for bitwise operations over binary data, particularly in settings where each participant holds a different part of the binary vector. This paper addresses the limitations of existing methods by proposing a novel binary multi-party computation (BiMPC) framework. The BiMPC mechanism facilitates
privacy-preserving bitwise operations, with a particular focus on dot product computations of binary vectors, ensuring the
privacy of each individual bit. The core of BiMPC is a novel approach called Dot Product via Modular Addition (DoMA), which uses regular and modular additions for efficient binary dot product calculation. To ensure
privacy, BiMPC uses random masking in a higher field for linear computations and a three-party oblivious transfer (triot) protocol for non-linear binary operations. The
privacy guarantees of the BiMPC framework are rigorously analyzed, demonstrating its efficiency and scalability in distributed settings.
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All authors Fatemeh Jafarian Dehkordi, Elahe Vedadi, Alireza Feizbakhsh, Yasaman Keshtkarjahromi, Hulya Seferoglu