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Computer Science Cryptography and Security

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Saturday 24 January

Cryptography and Security

Safeguard: Security Controls at the Software Defined Network Layer

Improvements in software defined networking allow for policy to be informed and modified by data-driven applications that can adjust policy to accommodate fluctuating requirements at line speed. However, there is some concern that over-correction can occur and cause unintended consequences depending on the data received. This is particularly problematic for network security features, such as machine-learning intrusion detection systems. We present Safeguard, a rule-based policy that overlaps a data-driven policy to prevent unintended responses for edge cases in network traffic. We develop a reference implementation of a network traffic classifier that enforces firewall rules for malicious traffic, and show how additional rulesets to allow known-good traffic are essential in utilizing a data-driven network policy.
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Cryptography and Security

On the Insecurity of Keystroke-Based AI Authorship Detection: Timing-Forgery Attacks Against Motor-Signal Verification

Recent proposals advocate using keystroke timing signals, specifically the coefficient of variation ($\delta$) of inter-keystroke intervals, to distinguish human-composed text from AI-generated content. We demonstrate that this class of defenses is insecure against two practical attack classes: the copy-type attack, in which a human transcribes LLM-generated text producing authentic motor signals, and timing-forgery attacks, in which automated agents sample inter-keystroke intervals from empirical human distributions. Using 13,000 sessions from the SBU corpus and three timing-forgery variants (histogram sampling, statistical impersonation, and generative LSTM), we show all attacks achieve $\ge$99.8% evasion rates against five classifiers. While detectors achieve AUC=1.000 against fully-automated injection, they classify $\ge$99.8% of attack samples as human with mean confidence $\ge$0.993. We formalize a non-identifiability result: when the detector observes only timing, the mutual information between features and content provenance is zero for copy-type attacks. Although composition and transcription produce statistically distinguishable motor patterns (Cohen's d=1.28), both yield $\delta$ values 2-4x above detection thresholds, rendering the distinction security-irrelevant. These systems confirm a human operated the keyboard, but not whether that human originated the text. Securing provenance requires architectures that bind the writing process to semantic content.
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Friday 23 January

Cryptography and Security · Cross-listed from cs.HC

Counterfactual Invariant Envelopes for Financial UX: Safety-Lattice Feature-Flag Governance in Crypto-Enabled Streaming

Feature flags are the primary mechanism for safely introducing financial capabilities in consumer applications. In crypto-enabled live streaming, however, naive rollouts can create non-obvious risk: users may be exposed to onramps without proper eligibility, external wallets without sufficient fraud controls, or advanced views that alter risk perception and behavior. This paper introduces a novel invention candidate, a Counterfactual Invariant Envelope governor that combines a safety lattice with causal measurement and a shadow cohort for risk estimation. We formalize rollout risk, define invariant constraints across feature combinations, and propose a controller that adapts exposure using leading abuse signals, compliance readiness, and revenue guardrails. We incorporate real-world adoption and fraud data for calibration, provide formulas for rollout safety, and include reproducible policy snippets. The results show that counterfactual, invariant-aware governance reduces risk spillover while preserving conversion and retention, offering a path to patentable governance logic for financial UX.
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Cryptography and Security

Toward Risk Thresholds for AI-Enabled Cyber Threats: Enhancing Decision-Making Under Uncertainty with Bayesian Networks

Artificial intelligence (AI) is increasingly being used to augment and automate cyber operations, altering the scale, speed, and accessibility of malicious activity. These shifts raise urgent questions about when AI systems introduce unacceptable or intolerable cyber risk, and how risk thresholds should be identified before harms materialize at scale. In recent years, industry, government, and civil society actors have begun to articulate such thresholds for advanced AI systems, with the goal of signaling when models meaningfully amplify cyber threats, for example, by automating multi-stage intrusions, enabling zero-day discovery, or lowering the expertise required for sophisticated attacks. However, current approaches to determine these thresholds remain fragmented and limited. Many thresholds rely solely on capability benchmarks or narrow threat scenarios, and are weakly connected to empirical evidence. This paper proposes a structured approach to developing and evaluating AI cyber risk thresholds that is probabilistic, evidence-based, and operationalizable. In this paper we make three core contributions that build on our prior work that highlights the limitations of relying solely on capability assessments. First, we analyze existing industry cyber thresholds and identify common threshold elements as well as recurring methodological shortcomings. Second, we propose the use of Bayesian networks as a tool for modeling AI-enabled cyber risk, enabling the integration of heterogeneous evidence, explicit representation of uncertainty, and continuous updating as new information emerges. Third, we illustrate this approach through a focused case study on AI-augmented phishing, demonstrating how qualitative threat insights can be decomposed into measurable variables and recombined into structured risk estimates that better capture how AI changes attacker behavior and outcomes.
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All authors Krystal Jackson, Deepika Raman, Jessica Newman, Nada Madkour, Charlotte Yuan, Evan R. Murphy

Cryptography and Security

TrojanGYM: A Detector-in-the-Loop LLM for Adaptive RTL Hardware Trojan Insertion

Hardware Trojans (HTs) remain a critical threat because learning-based detectors often overfit to narrow trigger/payload patterns and small, stylized benchmarks. We introduce TrojanGYM, an agentic, LLM-driven framework that automatically curates HT insertions to expose detector blind spots. Given high-level HT specifications, a suite of cooperating LLM agents (instantiated with GPT-4, LLaMA-3.3-70B, Gemini-2.5Pro, and Claude Opus 4.5) proposes and refines RTL modifications that realize diverse triggers and payloads without impacting functionality of both the HT and the design under attack. TrojanGYM implements an agentic loop co-designed with HT detectors, in which constraint-aware syntactic checking, testbench-based functional verification, and GNN-based HT detectors provide feedback that iteratively refines HT specifications and insertion strategies to better surface detector blind spots. We further propose Robust-GNN4TJ, a new implementation of GNN4TJ with improved graph extraction, training robustness, and prediction reliability, especially on LLM-generated HT designs. On the most challenging TrojanGYM-generated benchmarks, Robust-GNN4TJ raises HT detection rates from 0% to 60% relative to prior art. We instantiate TrojanGYM on SRAM, AES-128, UART, and RISC-V designs at RTL, and show that it systematically produces diverse, functionally correct HTs that reach up to 68.75% evasion rates against modern GNN-based detectors, revealing robustness gaps that are not apparent when these detectors are evaluated on existing TrustHub-style benchmarks. We release all codes and artifacts at https://github.com/DfX-NYUAD/TrojanGYM.
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All authors Saideep Sreekumar, Zeng Wang, Akashdeep Saha, Weihua Xiao, Minghao Shao, Muhammad Shafique, Ozgur Sinanoglu, Ramesh Karri, Johann Knechtel

Cryptography and Security · Cross-listed from math.NT

Logarithmic Density of Rank $\geq 1$ and Rank $\geq 2$ Genus-2 Jacobians and Applications to Hyperelliptic Curve Cryptography

In this work we study quantitative existence results for genus-$2$ curves over $\mathbb{Q}$ whose Jacobians have Mordell–Weil rank at least $1$ or $2$, ordering the curves by the naive height of their integral Weierstrass models. We use geometric techniques to show that asymptotically the Jacobians of almost all integral models with two rational points at infinity have rank $r \geq 1$. Since there are $\asymp X^{\frac{13}{2}}$ such models among the $X^7$ curves $y^2=f(x)$ of height at most $X$, this yields a lower bound of logarithmic density $13/14$ for the subset of such curves whose Jacobians have rank at least $1$. We further present a large explicit subfamily of genus-$2$ curves, ordered by height as above, for which the Jacobians have rank $r \geq 2$, yielding an unconditional logarithmic density of at least $5/7$. Independently, we give a construction of genus-$2$ curves with split Jacobian and rank at least $2$, producing a subfamily of logarithmic density at least $2/21$. Finally, we analyze quadratic and biquadratic twist families in the split-Jacobian setting, obtaining a positive proportion of rank-$2$ twists. These results have implications for Regev's quantum algorithm in hyperelliptic curve cryptography.
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All authors Razvan Barbulescu, Mugurel Barcau, Vicentiu Pasol, George C. Turcas

Cryptography and Security · Cross-listed from cs.LG

Learning to Collaborate: An Orchestrated-Decentralized Framework for Peer-to-Peer LLM Federation

Fine-tuning Large Language Models (LLMs) for specialized domains is constrained by a fundamental challenge: the need for diverse, cross-organizational data conflicts with the principles of data privacy and sovereignty. While Federated Learning (FL) provides a framework for collaboration without raw data exchange, its classic centralized form introduces a single point of failure and remains vulnerable to model inversion attacks. Decentralized FL (DFL) mitigates this risk by removing the central aggregator but typically relies on inefficient, random peer-to-peer (P2P) pairings, forming a collaboration graph that is blind to agent heterogeneity and risks negative transfer. This paper introduces KNEXA-FL, a novel framework for orchestrated decentralization that resolves this trade-off. KNEXA-FL employs a non-aggregating Central Profiler/Matchmaker (CPM) that formulates P2P collaboration as a contextual bandit problem, using a LinUCB algorithm on abstract agent profiles to learn an optimal matchmaking policy. It orchestrates direct knowledge exchange between heterogeneous, PEFT-based LLM agents via secure distillation, without ever accessing the models themselves. Our comprehensive experiments on a challenging code generation task show that KNEXA-FL yields substantial gains, improving Pass@1 by approx. 50% relative to random P2P collaboration. Critically, our orchestrated approach demonstrates stable convergence, in stark contrast to a powerful centralized distillation baseline which suffers from catastrophic performance collapse. Our work establishes adaptive, learning-based orchestration as a foundational principle for building robust and effective decentralized AI ecosystems.
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All authors Inderjeet Singh, Eleonore Vissol-Gaudin, Andikan Otung, Motoyoshi Sekiya

Cryptography and Security · Cross-listed from cs.LG

Impact of Graph Structure on Membership-Inference Risk for Graph Neural Networks

Graph neural networks (GNNs) are widely used for tasks such as node classification and link prediction, but their use in sensitive settings raises concerns about training-data leakage. Prior work on privacy leakage in GNNs largely borrows assumptions from non-graph domains, overlooking the role of graph structure. We argue for a graph-specific analysis of privacy risk and study how graph structure affects node-level membership inference. We formalize membership inference (MI) over node-neighborhood tuples and investigate two important dimensions: (i) training-graph construction and (ii) inference-time edge access. We compare snowball sampling, a structure-aware procedure, with uniform random node sampling for constructing training graphs. Our experiments show that snowball sampling often hurts generalization relative to random sampling due to its coverage bias. In contrast, allowing access to inter-train-test edges at inference improves test accuracy, reduces the train-test gap, while also having a strong and setting-dependent effect on membership advantage. These results show that graph structure directly shapes privacy risk. We further show that the generalization gap, measured as the performance difference between training and test nodes, is an incomplete proxy for membership inference risk: membership advantage can rise or fall independently of changes in this gap, with inference-time edge access often playing a crucial role. Theoretically, we show that for node-level tasks, standard privacy-auditing results based on membership inference do not directly carry over to inductive graph settings, because training and test nodes are structurally dependent rather than interchangeable. We release the code and data at https://github.com/PriXAI/GraphStructurePrivacyAnalysis-public.
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Cryptography and Security

Contagion Effects of Heterogeneous Cyber Risk on Network Security and Systemic Stability

Understanding how heterogeneous cyber risk shapes security investments and contagion is a key challenge for the resilience of interconnected digital systems. Existing studies on cybersecurity investments and network contagion typically rely on homogeneous assets, uniform attack incentives, or non-strategic threat propagation. We develop a Stackelberg security game that combines contagion dynamics with heterogeneous cyber risk, allowing attackers and defenders to assign different values to network nodes, reflecting differences in asset criticality, information, and objectives. We characterize the equilibrium allocation of cybersecurity investments and derive an analytical approximation for the optimal defense strategy based on endogenous network protection metrics. We show that cyber-risk heterogeneity significantly affects attack incentives and resource allocation, while neglecting it leads to systematic defense misallocation. Our results suggest that cybersecurity policies should leverage both actual and perceived differences in node criticality, as cyber-deception mechanisms can create strategic misperceptions that redirect attacks and enhance systemic resilience.
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All authors Elisa Botteghi, Martino S. Centonze, Davide Pastorello, Daniele Tantari

Cryptography and Security

Building a Robust Risk-Based Access Control System to Combat Ransomware's Capability to Encrypt

Ransomware core capability, unauthorized encryption, demands controls that identify and block malicious cryptographic activity without disrupting legitimate use. We present a probabilistic, risk-based access control architecture that couples machine learning inference with mandatory access control to regulate encryption on Linux in real time. The system builds a specialized dataset from the native ftrace framework using the function_graph tracer, yielding high-resolution kernel-function execution traces augmented with resource and I/O counters. These traces support both a supervised classifier and interpretable rules that drive an SELinux policy via lightweight booleans, enabling context-sensitive permit/deny decisions at the moment encryption begins. Compared to approaches centered on sandboxing, hypervisor introspection, or coarse system-call telemetry, the function-level tracing we adopt provides finer behavioral granularity than syscall-only telemetry while avoiding the virtualization/VMI overhead of sandbox-based approaches. Our current user-space prototype has a non-trivial footprint under burst I/O; we quantify it and recognize that a production kernel-space solution should aim to address this. We detail dataset construction, model training and rule extraction, and the run-time integration that gates file writes for suspect encryption while preserving benign cryptographic workflows. During evaluation, the two-layer composition retains model-level detection quality while delivering rule-like responsiveness; we also quantify operational footprint and outline engineering steps to reduce CPU and memory overhead for enterprise deployment. The result is a practical path from behavioral tracing and learning to enforceable, explainable, and risk-proportionate encryption control on production Linux systems.
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Cryptography and Security · Cross-listed from cs.HC

"What I Sign Is Not What I See": Towards Explainable and Trustworthy Cryptocurrency Wallet Signatures

Cryptocurrency wallets have become the primary gateway to decentralized applications, yet users often face significant difficulty in discerning what a wallet signature actually does or entails. Prior work has mainly focused on mitigating protocol vulnerabilities, with limited attention to how users perceive and interpret what they are authorizing. To examine this usability-security gap, we conducted two formative studies investigating how users interpret authentic signing requests and what cues they rely on to assess risk. Findings reveal that users often misread critical parameters, underestimate high-risk signatures, and rely on superficial familiarity rather than understanding transaction intent. Building on these insights, we designed the Signature Semantic Decoder – a prototype framework that reconstructs and visualizes the intent behind wallet signatures prior to confirmation. Through structured parsing and semantic labeling, it demonstrates how signing data can be transformed into plain-language explanations with contextual risk cues. In a between-subjects user study (N = 128), participants using the prototype achieved higher accuracy in identifying risky signatures, improved clarity and decision confidence, and lower cognitive workload compared with the baseline wallet interface. Our study reframes wallet signing as a problem of interpretability within secure interaction design and offers design implications for more transparent and trustworthy cryptocurrency wallet interfaces.
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Cryptography and Security

From Transactions to Exploits: Automated PoC Synthesis for Real-World DeFi Attacks

Blockchain systems are increasingly targeted by on-chain attacks that exploit contract vulnerabilities to extract value rapidly and stealthily, making systematic analysis and reproduction highly challenging. In practice, reproducing such attacks requires manually crafting proofs-of-concept (PoCs), a labor-intensive process that demands substantial expertise and scales poorly. In this work, we present the first automated framework for synthesizing verifiable PoCs directly from on-chain attack executions. Our key insight is that attacker logic can be recovered from low-level transaction traces via trace-driven reverse engineering, and then translated into executable exploits by leveraging the code-generation capabilities of large language models (LLMs). To this end, we propose TracExp, which localizes attack-relevant execution contexts from noisy, multi-contract traces and introduces a novel dual-decompiler to transform concrete executions into semantically enriched exploit pseudocode. Guided by this representation, TracExp synthesizes PoCs and refines them to preserve exploitability-relevant semantics. We evaluate TracExp on 321 real-world attacks over the past 20 months. TracExp successfully synthesizes PoCs for 93% of incidents, with 58.78% being directly verifiable, at an average cost of only \$0.07 per case. Moreover, TracExp enabled the release of a large number of previously unavailable PoCs to the community, earning a $900 bounty and demonstrating strong practical impact.
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All authors Xing Su, Hao Wu, Hanzhong Liang, Yunlin Jiang, Yuxi Cheng, Yating Liu, Fengyuan Xu

Cryptography and Security

Emerging Threats and Countermeasures in Neuromorphic Systems: A Survey

Neuromorphic computing mimics brain-inspired mechanisms through spiking neurons and energy-efficient processing, offering a pathway to efficient in-memory computing (IMC). However, these advancements raise critical security and privacy concerns. As the adoption of bio-inspired architectures and memristive devices increases, so does the urgency to assess the vulnerability of these emerging technologies to hardware and software attacks. Emerging architectures introduce new attack surfaces, particularly due to asynchronous, event-driven processing and stochastic device behavior. The integration of memristors into neuromorphic hardware and software implementations in spiking neural networks offers diverse possibilities for advanced computing architectures, including their role in security-aware applications. This survey systematically analyzes the security landscape of neuromorphic systems, covering attack methodologies, side-channel vulnerabilities, and countermeasures. We focus on both hardware and software concerns relevant to spiking neural networks (SNNs) and hardware primitives, such as Physical Unclonable Functions (PUFs) and True Random Number Generators (TRNGs) for cryptographic and secure computation applications. We approach this analysis from diverse perspectives, from attack methodologies to countermeasure strategies that integrate efficiency and protection in brain-inspired hardware. This review not only maps the current landscape of security threats but provides a foundation for developing secure and trustworthy neuromorphic architectures.
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All authors Pablo Sorrentino, Stjepan Picek, Ihsen Alouani, Nikolaos Athanasios Anagnostopoulos, Francesco Regazzoni, Lejla Batina, Tamalika Banerjee, Fatih Turkmen

Cryptography and Security

Eclipse Attacks on Ethereum's Peer-to-Peer Network

Eclipse attacks isolate blockchain nodes by monopolizing their peer-to-peer connections. The attacks were extensively studied in Bitcoin (SP'15, SP'20, CCS'21, SP'23) and Monero (NDSS'25), but their practicality against Ethereum nodes remains underexplored, particularly in the post-Merge settings. We present the first end-to-end implementation of an eclipse attack targeting Ethereum (2.0 version) execution-layer nodes. Our attack exploits the bootstrapping and peer management logic of Ethereum to fully isolate a node upon restart. We introduce a multi-stage strategy that majorly includes (i) poisoning the node's discovery table via unsolicited messages, (ii) infiltrating Ethereum's DNS-based peerlist by identifying and manipulating the official DNS crawler, and (iii) hijacking idle incoming connection slots across the network to block benign connections. Our DNS list poisoning is the first in the cryptocurrency context and requires only 28 IP addresses over 100 days. Slots hijacking raises outgoing redirection success from 45% to 95%. We validate our approach through controlled experiments on Ethereum's Sepolia testnet and broad measurements on the mainnet. Our findings demonstrate that over 80% of public nodes do not leave sufficient idle capacity for effective slots occupation, highlighting the feasibility and severity of the threat. We further propose concrete countermeasures and responsibly disclosed all findings to Ethereum's security team.
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All authors Ruisheng Shi, Yuxuan Liang, Zijun Guo, Qin Wang, Lina Lan, Chenfeng Wang, Zhuoyi Zheng

Cryptography and Security

SafeThinker: Reasoning about Risk to Deepen Safety Beyond Shallow Alignment

Despite the intrinsic risk-awareness of Large Language Models (LLMs), current defenses often result in shallow safety alignment, rendering models vulnerable to disguised attacks (e.g., prefilling) while degrading utility. To bridge this gap, we propose SafeThinker, an adaptive framework that dynamically allocates defensive resources via a lightweight gateway classifier. Based on the gateway's risk assessment, inputs are routed through three distinct mechanisms: (i) a Standardized Refusal Mechanism for explicit threats to maximize efficiency; (ii) a Safety-Aware Twin Expert (SATE) module to intercept deceptive attacks masquerading as benign queries; and (iii) a Distribution-Guided Think (DDGT) component that adaptively intervenes during uncertain generation. Experiments show that SafeThinker significantly lowers attack success rates across diverse jailbreak strategies without compromising utility, demonstrating that coordinating intrinsic judgment throughout the generation process effectively balances robustness and practicality.
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All authors Xianya Fang, Xianying Luo, Yadong Wang, Xiang Chen, Yu Tian, Zequn Sun, Rui Liu, Jun Fang, Naiqiang Tan, Yuanning Cui, Sheng-Jun Huang

Cryptography and Security

A High Performance and Efficient Post-Quantum Crypto-Processor for FrodoKEM

FrodoKEM is a lattice-based post-quantum key encapsulation mechanism (KEM). It has been considered for standardization by the International Organization for Standardization (ISO) due to its robust security profile. However, its hardware implementation exhibits a weakness of high latency and heavy resource burden, hindering its practical application. Moreover, diverse usage scenarios call for comprehensive functionality. To address these challenges, this paper presents a high-performance and efficient crypto-processor for FrodoKEM. A multiple-instruction overlapped execution scheme is introduced to enable efficient multi-module scheduling and minimize operational latency. Furthermore, a high-speed, reconfigurable parallel multiplier array is integrated to handle intensive matrix computations under diverse computation patterns, significantly enhancing hardware efficiency. In addition, a compact memory scheduling strategy shortens the lifespan of intermediate matrices, thereby reducing overall storage requirements. The proposed design provides full support for all FrodoKEM security levels and protocol phases. It consumes 13467 LUTs, 6042 FFs, and 14 BRAMs on an Artix-7 FPGA and achieves the fastest reported execution time. Compared with state-of-the-art hardware implementations, our design improves the area-time product (ATP) by 1.75-2.00 times.
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All authors Kai Li, Jiahao Lu, Fu Yao, Guang Zeng, Dongsheng Liu, Shengfei Gu, Zhengpeng Zhao, Jiachen Wang

Cryptography and Security

DeMark: A Query-Free Black-Box Attack on Deepfake Watermarking Defenses

The rapid proliferation of realistic deepfakes has raised urgent concerns over their misuse, motivating the use of defensive watermarks in synthetic images for reliable detection and provenance tracking. However, this defense paradigm assumes such watermarks are inherently resistant to removal. We challenge this assumption with DeMark, a query-free black-box attack framework that targets defensive image watermarking schemes for deepfakes. DeMark exploits latent-space vulnerabilities in encoder-decoder watermarking models through a compressive sensing based sparsification process, suppressing watermark signals while preserving perceptual and structural realism appropriate for deepfakes. Across eight state-of-the-art watermarking schemes, DeMark reduces watermark detection accuracy from 100% to 32.9% on average while maintaining natural visual quality, outperforming existing attacks. We further evaluate three defense strategies, including image super resolution, sparse watermarking, and adversarial training, and find them largely ineffective. These results demonstrate that current encoder decoder watermarking schemes remain vulnerable to latent-space manipulations, underscoring the need for more robust watermarking methods to safeguard against deepfakes.
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All authors Wei Song, Zhenchang Xing, Liming Zhu, Yulei Sui, Jingling Xue

Cryptography and Security

Secure Intellicise Wireless Network: Agentic AI for Coverless Semantic Steganography Communication

Semantic Communication (SemCom), leveraging its significant advantages in transmission efficiency and reliability, has emerged as a core technology for constructing future intellicise (intelligent and concise) wireless networks. However, intelligent attacks represented by semantic eavesdropping pose severe challenges to the security of SemCom. To address this challenge, Semantic Steganographic Communication (SemSteCom) achieves “invisible” encryption by implicitly embedding private semantic information into cover modality carriers. The state-of-the-art study has further introduced generative diffusion models to directly generate stega images without relying on original cover images, effectively enhancing steganographic capacity. Nevertheless, the recovery process of private images is highly dependent on the guidance of private semantic keys, which may be inferred by intelligent eavesdroppers, thereby introducing new security threats. To address this issue, we propose an Agentic AI-driven SemSteCom (AgentSemSteCom) scheme, which includes semantic extraction, digital token controlled reference image generation, coverless steganography, semantic codec, and optional task-oriented enhancement modules. The proposed AgentSemSteCom scheme obviates the need for both cover images and private semantic keys, thereby boosting steganographic capacity while reinforcing transmission security. The simulation results on open-source datasets verify that, AgentSemSteCom achieves better transmission quality and higher security levels than the baseline scheme.
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All authors Rui Meng, Song Gao, Bingxuan Xu, Xiaodong Xu, Jianqiao Chen, Nan Ma, Pei Xiao, Ping Zhang, Rahim Tafazolli

Cryptography and Security

Cutting the Gordian Knot: Detecting Malicious PyPI Packages via a Knowledge-Mining Framework

The Python Package Index (PyPI) has become a target for malicious actors, yet existing detection tools generate false positive rates of 15-30%, incorrectly flagging one-third of legitimate packages as malicious. This problem arises because current tools rely on simple syntactic rules rather than semantic understanding, failing to distinguish between identical API calls serving legitimate versus malicious purposes. To address this challenge, we propose PyGuard, a knowledge-driven framework that converts detection failures into useful behavioral knowledge by extracting patterns from existing tools' false positives and negatives. Our method utilizes hierarchical pattern mining to identify behavioral sequences that distinguish malicious from benign code, employs Large Language Models to create semantic abstractions beyond syntactic variations, and combines this knowledge into a detection system that integrates exact pattern matching with contextual reasoning. PyGuard achieves 99.50% accuracy with only 2 false positives versus 1,927-2,117 in existing tools, maintains 98.28% accuracy on obfuscated code, and identified 219 previously unknown malicious packages in real-world deployment. The behavioral patterns show cross-ecosystem applicability with 98.07% accuracy on NPM packages, demonstrating that semantic understanding enables knowledge transfer across programming languages.
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All authors Wenbo Guo, Chengwei Liu, Ming Kang, Yiran Zhang, Jiahui Wu, Zhengzi Xu, Vinay Sachidananda, Yang Liu

Cryptography and Security · Cross-listed from cs.SE

Bridging Expert Reasoning and LLM Detection: A Knowledge-Driven Framework for Malicious Packages

Open-source ecosystems such as NPM and PyPI are increasingly targeted by supply chain attacks, yet existing detection methods either depend on fragile handcrafted rules or data-driven features that fail to capture evolving attack semantics. We present IntelGuard, a retrieval-augmented generation (RAG) based framework that integrates expert analytical reasoning into automated malicious package detection. IntelGuard constructs a structured knowledge base from over 8,000 threat intelligence reports, linking malicious code snippets with behavioral descriptions and expert reasoning. When analyzing new packages, it retrieves semantically similar malicious examples and applies LLM-guided reasoning to assess whether code behaviors align with intended functionality. Experiments on 4,027 real-world packages show that IntelGuard achieves 99% accuracy and a 0.50% false positive rate, while maintaining 96.5% accuracy on obfuscated code. Deployed on PyPI.org, it discovered 54 previously unreported malicious packages, demonstrating interpretable and robust detection guided by expert knowledge.
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All authors Wenbo Guo, Shiwen Song, Jiaxun Guo, Zhengzi Xu, Chengwei Liu, Haoran Ou, Mengmeng Ge, Yang Liu

Cryptography and Security

Ringmaster: How to juggle high-throughput host OS system calls from TrustZone TEEs

Many safety-critical systems require timely processing of sensor inputs to avoid potential safety hazards. Additionally, to support useful application features, such systems increasingly have a large rich operating system (OS) at the cost of potential security bugs. Thus, if a malicious party gains supervisor privileges, they could cause real-world damage by denying service to time-sensitive programs. Many past approaches to this problem completely isolate time-sensitive programs with a hypervisor; however, this prevents the programs from accessing useful OS services. We introduce Ringmaster, a novel framework that enables enclaves or TEEs (Trusted Execution Environments) to asynchronously access rich, but potentially untrusted, OS services via Linux's io_uring. When service is denied by the untrusted OS, enclaves continue to operate on Ringmaster's minimal ARM TrustZone kernel with access to small, critical device drivers. This approach balances the need for secure, time-sensitive processing with the convenience of rich OS services. Additionally, Ringmaster supports large unmodified programs as enclaves, offering lower overhead compared to existing systems. We demonstrate how Ringmaster helps us build a working highly-secure system with minimal engineering. In our experiments with an unmanned aerial vehicle, Ringmaster achieved nearly 1GiB/sec of data into enclave on a Raspberry Pi4b, 0-3% throughput overhead compared to non-enclave tasks.
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All authors Richard Habeeb, Man-Ki Yoon, Hao Chen, Zhong Shao

Thursday 22 January

Cryptography and Security

NOIR: Privacy-Preserving Generation of Code with Open-Source LLMs

Although boosting software development performance, large language model (LLM)-powered code generation introduces intellectual property and data security risks rooted in the fact that a service provider (cloud) observes a client's prompts and generated code, which can be proprietary in commercial systems. To mitigate this problem, we propose NOIR, the first framework to protect the client's prompts and generated code from the cloud. NOIR uses an encoder and a decoder at the client to encode and send the prompts' embeddings to the cloud to get enriched embeddings from the LLM, which are then decoded to generate the code locally at the client. Since the cloud can use the embeddings to infer the prompt and the generated code, NOIR introduces a new mechanism to achieve indistinguishability, a local differential privacy protection at the token embedding level, in the vocabulary used in the prompts and code, and a data-independent and randomized tokenizer on the client side. These components effectively defend against reconstruction and frequency analysis attacks by an honest-but-curious cloud. Extensive analysis and results using open-source LLMs show that NOIR significantly outperforms existing baselines on benchmarks, including the Evalplus (MBPP and HumanEval, Pass@1 of 76.7 and 77.4), and BigCodeBench (Pass@1 of 38.7, only a 1.77% drop from the original LLM) under strong privacy against attacks.
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All authors Khoa Nguyen, Khiem Ton, NhatHai Phan, Issa Khalil, Khang Tran, Cristian Borcea, Ruoming Jin, Abdallah Khreishah, My T. Thai

Cryptography and Security

FC-GUARD: Enabling Anonymous yet Compliant Fiat-to-Cryptocurrency Exchanges

With the rise of decentralized finance, fiat-to-cryptocurrency exchange platforms have become popular entry points into the cryptocurrency ecosystem. However, these platforms frequently fail to ensure adequate privacy protection, as evidenced by real-world breaches that exposed personally identifiable information (PII) and crypto addresses. Such leaks enable adversaries to link real-world identities to cryptocurrency transactions, undermining the presumed anonymity of cryptocurrency use. We propose FC-GUARD, a privacy-preserving exchange system designed to preserve user anonymity without compromising regulatory compliance in the exchange of fiat currency for cryptocurrencies. Leveraging verifiable credentials and zero-knowledge proof techniques, FC-GUARD enables fiat-to-cryptocurrency exchanges without revealing users' PII or fiat account details. This breaks the linkage between users' real-world identities and their cryptocurrency addresses, thereby upholding anonymity, a fundamental expectation in the cryptocurrency ecosystem. In addition, FC-GUARD complies with key regulations over cryptocurrency usage, such as know-your-customer requirements and auditability for tax reporting obligations by integrating a lawful de-anonymization mechanism that allows the auditing authority to identify misbehaving users. This ensures regulatory compliance while defaulting to privacy protection. We implement our system on both desktop and mobile platforms, and our evaluation shows its feasibility for practical deployment.
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All authors Shaoyu Li, Hexuan Yu, Md Mohaimin Al Barat, Yang Xiao, Y. Thomas Hou, Wenjing Lou

Cryptography and Security

Adaptive Attribute-Decoupled Encryption for Trusted Respiratory Monitoring in Resource-Limited Consumer Healthcare

Respiratory monitoring is an extremely important task in modern medical services. Due to its significant advantages, e.g., non-contact, radar-based respiratory monitoring has attracted widespread attention from both academia and industry. Unfortunately, though it can achieve high monitoring accuracy, consumer electronics-grade radar data inevitably contains User-sensitive Identity Information (USI), which may be maliciously used and further lead to privacy leakage. To track these challenges, by variational mode decomposition (VMD) and adversarial loss-based encryption, we propose a novel Trusted Respiratory Monitoring paradigm, Tru-RM, to perform automated respiratory monitoring through radio signals while effectively anonymizing USI. The key enablers of Tru-RM are Attribute Feature Decoupling (AFD), Flexible Perturbation Encryptor (FPE), and robust Perturbation Tolerable Network (PTN) used for attribute decomposition, identity encryption, and perturbed respiratory monitoring, respectively. Specifically, AFD is designed to decompose the raw radar signals into the universal respiratory component, the personal difference component, and other unrelated components. Then, by using large noise to drown out the other unrelated components, and the phase noise algorithm with a learning intensity parameter to eliminate USI in the personal difference component, FPE is designed to achieve complete user identity information encryption without affecting respiratory features. Finally, by designing the transferred generalized domain-independent network, PTN is employed to accurately detect respiration when waveforms change significantly. Extensive experiments based on various detection distances, respiratory patterns, and durations demonstrate the superior performance of Tru-RM on strong anonymity of USI, and high detection accuracy of perturbed respiratory waveforms.
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All authors Xinyu Li, Jinyang Huang, Feng-Qi Cui, Meng Wang, Peng Zhao, Meng Li, Dan Guo, Meng Wang

Cryptography and Security

PAL*M: Property Attestation for Large Generative Models

Machine learning property attestations allow provers (e.g., model providers or owners) to attest properties of their models/datasets to verifiers (e.g., regulators, customers), enabling accountability towards regulations and policies. But, current approaches do not support generative models or large datasets. We present PAL*M, a property attestation framework for large generative models, illustrated using large language models. PAL*M defines properties across training and inference, leverages confidential virtual machines with security-aware GPUs for coverage of CPU-GPU operations, and proposes using incremental multiset hashing over memory-mapped datasets to efficiently track their integrity. We implement PAL*M on Intel TDX+NVIDIA H100 and evaluate it using state-of-the-art models and datasets, showing PAL*M is efficient, incurring < 11% overhead for common operations. Finally, we use the Tamarin Prover symbolic verification tool to formally model PAL*M's property attestation protocol, confirming that its security guarantees are upheld under the defined threat model.
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All authors Prach Chantasantitam, Adam Ilyas Caulfield, Vasisht Duddu, Lachlan J. Gunn, N. Asokan

Cryptography and Security

CONTEX-T: Contextual Exploitation of Encrypted Traffic for Device Fingerprinting via Transformer Time-Frequency Analysis

The rapid expansion of internet of things (IoT) devices has created a pervasive ecosystem where encrypted wireless communications serve as the primary privacy and security protection mechanism. While encryption effectively protects message content, contextual information from packet metadata and statistics inadvertently expose device identities. Various studies have exploited raw packet statistics and their visual representations for device fingerprinting and identification. However, these approaches remain confined to the spatial domain with limited feature representation. Therefore, this paper presents CONTEX-T, a novel framework that exploits device-level information from encrypted traffic metadata using temporal and spectral representation. The experiments show that time-frequency analysis provides new and rich feature representation, revealing a complex and expanding threat landscape that would require robust countermeasures for IoT security management. CONTEX-T first transforms raw packet-length sequences into temporal and spectral representations and then utilizes vision transformers (ViTs) for device identification. We systematically evaluated multiple time-frequency representation techniques and transformer-based models across encrypted traffic samples from various IoT devices. CONTEX-T achieved device classification accuracy exceeding 99% while operating passively on observable contextual metadata. This demonstrates that temporal and spectral signatures persist under strong encryption, highlighting a critical attack surface for IoT network security and management.
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Cryptography and Security · Cross-listed from cs.CV

Learning to Watermark in the Latent Space of Generative Models

Existing approaches for watermarking AI-generated images often rely on post-hoc methods applied in pixel space, introducing computational overhead and potential visual artifacts. In this work, we explore latent space watermarking and introduce DistSeal, a unified approach for latent watermarking that works across both diffusion and autoregressive models. Our approach works by training post-hoc watermarking models in the latent space of generative models. We demonstrate that these latent watermarkers can be effectively distilled either into the generative model itself or into the latent decoder, enabling in-model watermarking. The resulting latent watermarks achieve competitive robustness while offering similar imperceptibility and up to 20x speedup compared to pixel-space baselines. Our experiments further reveal that distilling latent watermarkers outperforms distilling pixel-space ones, providing a solution that is both more efficient and more robust.
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All authors Sylvestre-Alvise Rebuffi, Tuan Tran, Valeriu Lacatusu, Pierre Fernandez, Tomáš Souček, Nikola Jovanović, Tom Sander, Hady Elsahar, Alexandre Mourachko

Cryptography and Security

Introducing the Generative Application Firewall (GAF)

This paper introduces the Generative Application Firewall (GAF), a new architectural layer for securing LLM applications. Existing defenses – prompt filters, guardrails, and data-masking – remain fragmented; GAF unifies them into a single enforcement point, much like a WAF coordinates defenses for web traffic, while also covering autonomous agents and their tool interactions.
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All authors Joan Vendrell Farreny, Martí Jordà Roca, Miquel Cornudella Gaya, Rodrigo Fernández Baón, Víctor García Martínez, Eduard Camacho Sucarrats, Alessandro Pignati

Cryptography and Security · Cross-listed from cs.LG

Attributing and Exploiting Safety Vectors through Global Optimization in Large Language Models

While Large Language Models (LLMs) are aligned to mitigate risks, their safety guardrails remain fragile against jailbreak attacks. This reveals limited understanding of components governing safety. Existing methods rely on local, greedy attribution that assumes independent component contributions. However, they overlook the cooperative interactions between different components in LLMs, such as attention heads, which jointly contribute to safety mechanisms. We propose Global Optimization for Safety Vector Extraction (GOSV), a framework that identifies safety-critical attention heads through global optimization over all heads simultaneously. We employ two complementary activation repatching strategies: Harmful Patching and Zero Ablation. These strategies identify two spatially distinct sets of safety vectors with consistently low overlap, termed Malicious Injection Vectors and Safety Suppression Vectors, demonstrating that aligned LLMs maintain separate functional pathways for safety purposes. Through systematic analyses, we find that complete safety breakdown occurs when approximately 30% of total heads are repatched across all models. Building on these insights, we develop a novel inference-time white-box jailbreak method that exploits the identified safety vectors through activation repatching. Our attack substantially outperforms existing white-box attacks across all test models, providing strong evidence for the effectiveness of the proposed GOSV framework on LLM safety interpretability.
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All authors Fengheng Chu, Jiahao Chen, Yuhong Wang, Jun Wang, Zhihui Fu, Shouling Ji, Songze Li

Cryptography and Security

FirmReBugger: A Benchmark Framework for Monolithic Firmware Fuzzers

Monolithic Firmware is widespread. Unsurprisingly, fuzz testing firmware is an active research field with new advances addressing the unique challenges in the domain. However, understanding and evaluating improvements by deriving metrics such as code coverage and unique crashes are problematic, leading to a desire for a reliable bug-based benchmark. To address the need, we design and build FirmReBugger, a holistic framework for fairly assessing monolithic firmware fuzzers with a realistic, diverse, bug-based benchmark. FirmReBugger proposes using bug oracles–C syntax expressions of bug descriptors–with an interpreter to automate analysis and accurately report on bugs discovered, discriminating between states of detected, triggered, reached and not reached. Importantly, our idea of benchmarking does not modify the target binary and simply replays fuzzing seeds to isolate the benchmark implementation from the fuzzer while providing a simple means to extend with new bug oracles. Further, analyzing fuzzing roadblocks, we created FirmBench, a set of diverse, real-world binary targets with 313 software bug oracles. Incorporating our analysis of roadblocks challenging monolithic firmware fuzzing, the bench provides for rapid evaluation of future advances. We implement FirmReBugger in a FuzzBench-for-Firmware type service and use FirmBench to evaluate 9 state-of-the art monolithic firmware fuzzers in the style of a reproducibility study, using a 10 CPU-year effort, to report our findings.
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All authors Mathew Duong, Michael Chesser, Guy Farrelly, Surya Nepal, Damith C. Ranasinghe