Cryptography and Security · Cross-listed from physics.soc-ph
Strategic Communication Protocols for Interstellar Objects Using a Threat-Communication Viability Index and the Information-Communication Paradox
David R. Gruber
Strategic Communication Protocols provide a structured approach for first contact with interstellar objects that demonstrate technological characteristics and high levels of threat. The protocols find their starting point in an ISO Information-Communication Paradox, namely, as our knowledge of an ISO's threatening capabilities increases, the probability of successful communication decreases while the urgency of communication attempts simultaneously intensifies. From this paradox, a Threat-Communication Viability Index is created to describe when the value of communication attempts outweighs strategic silence. The index scores the situation and operates as a decision-making tool for stakeholders tracking an ISO. The communication protocols subsequently outline several diplomatic strategies in cases where the index recommends communication.
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Cryptography and Security · Cross-listed from cs.AI
How Catastrophic is Your LLM? Certifying Risk in Conversation
Chengxiao Wang, Isha Chaudhary, Qian Hu et al. (+3 more)
Large
Language Models (LLMs) can produce catastrophic responses in conversational settings that pose serious risks to public safety and security. Existing evaluations often fail to fully reveal these vulnerabilities because they rely on fixed attack
prompt sequences, lack statistical guarantees, and do not scale to the vast space of multi-turn conversations. In this work, we propose C$^3$LLM, a novel, principled statistical Certification framework for Catastrophic risks in multi-turn Conversation for LLMs that bounds the probability of an LLM generating catastrophic responses under multi-turn conversation distributions with statistical guarantees. We model multi-turn conversations as probability distributions over query sequences, represented by a Markov process on a query graph whose edges encode semantic similarity to capture realistic conversational flow, and quantify catastrophic risks using confidence intervals. We define several inexpensive and practical distributions–random node, graph path, and adaptive with rejection. Our results demonstrate that these distributions can reveal substantial catastrophic risks in frontier models, with certified lower bounds as high as 70% for the worst model, highlighting the urgent need for improved safety training strategies in frontier LLMs.
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All authors Chengxiao Wang, Isha Chaudhary, Qian Hu, Weitong Ruan, Rahul Gupta, Gagandeep Singh
Cryptography and Security · Cross-listed from cs.AI
Spatial CAPTCHA: Generatively Benchmarking Spatial Reasoning for Human-Machine Differentiation
Arina Kharlamova, Bowei He, Chen Ma et al. (+1 more)
Online services rely on CAPTCHAs as a first line of defense against automated abuse, yet recent advances in multi-modal large
language models (MLLMs) have eroded the effectiveness of conventional designs that focus on text recognition or 2D image understanding. To address this challenge, we present Spatial CAPTCHA, a novel human-verification framework that leverages fundamental differences in spatial
reasoning between humans and MLLMs. Unlike existing CAPTCHAs which rely on low-level perception tasks that are vulnerable to modern AI, Spatial CAPTCHA generates dynamic questions requiring
geometric reasoning, perspective-taking, occlusion handling, and mental rotation. These skills are intuitive for humans but difficult for state-of-the-art (SOTA) AI systems. The system employs a procedural generation pipeline with constraint-based difficulty control, automated correctness verification, and human-in-the-loop validation to ensure scalability, robustness, and adaptability. Evaluation on a corresponding
benchmark, Spatial-CAPTCHA-Bench, demonstrates that humans vastly outperform 10 state-of-the-art MLLMs, with the best model achieving only 31.0% Pass@1 accuracy. Furthermore, we compare Spatial CAPTCHA with Google reCAPTCHA, which confirms its effectiveness as both a security mechanism and a diagnostic tool for spatial
reasoning in AI.
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All authors Arina Kharlamova, Bowei He, Chen Ma, Xue Liu
Cryptography and Security
Detecting Malicious Pilot Contamination in Multiuser Massive MIMO Using Decision Trees
Pedro Ivo da Cruz, Dimitri Silva, Tito Spadini et al. (+2 more)
Massive multiple-input multiple-output (MMIMO) is essential to modern wireless communication systems, like 5G and 6G, but it is vulnerable to active eavesdropping attacks. One type of such attack is the pilot contamination attack (PCA), where a malicious user copies pilot signals from an authentic user during uplink, intentionally interfering with the base station's (BS) channel estimation accuracy. In this work, we propose to use a Decision Tree (DT)
algorithm for PCA detection at the BS in a multi-user system. We present a methodology to generate training data for the DT classifier and select the best DT according to their depth. Then, we simulate different scenarios that could be encountered in practice and compare the DT to a classical technique based on likelihood ratio testing (LRT) submitted to the same scenarios. The results revealed that a DT with only one level of depth is sufficient to outperform the LRT. The DT shows a good performance regarding the probability of detection in noisy scenarios and when the malicious user transmits with low power, in which case the LRT fails to detect the PCA. We also show that the reason for the good performance of the DT is its ability to compute a threshold that separates PCA data from non-PCA data better than the LRT's threshold. Moreover, the DT does not necessitate prior knowledge of noise power or assumptions regarding the signal power of malicious users, prerequisites typically essential for LRT and other hypothesis testing methodologies.
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All authors Pedro Ivo da Cruz, Dimitri Silva, Tito Spadini, Ricardo Suyama, Murilo Bellezoni Loiola
Cryptography and Security
Security Analysis of Ponzi Schemes in Ethereum Smart Contracts
Chunyi Zhang, Qinghong Wei and Xiaoqi Li
The rapid advancement of blockchain technology has precipitated the widespread adoption of Ethereum and smart contracts across a variety of sectors. However, this has also given rise to numerous fraudulent activities, with many speculators
embedding Ponzi schemes within smart contracts, resulting in significant financial losses for investors. Currently, there is a lack of effective methods for identifying and analyzing such new types of fraudulent activities. This paper categorizes these scams into four structural types and explores the intrinsic characteristics of Ponzi scheme contract source code from a program analysis perspective. The Mythril tool is employed to conduct static and dynamic analyses of representative cases, thereby revealing their vulnerabilities and operational mechanisms. Furthermore, this paper employs shell scripts and command patterns to conduct batch detection of open-source smart contract code, thereby unveiling the common characteristics of Ponzi scheme smart contracts.
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Cryptography and Security
Complex domain approach for reversible data hiding and homomorphic encryption: General framework and application to dispersed data
David Megias
Ensuring the trustworthiness of data from distributed and resource-constrained environments, such as Wireless Sensor Networks or IoT devices, is critical. Existing Reversible Data Hiding (RDH) methods for scalar data suffer from low
embedding capacity and poor intrinsic
entanglement between host data and watermark. This paper introduces Hiding in the Imaginary Domain with Data Encryption (H[$i$]dden), a novel framework based on complex number arithmetic for simultaneous information
embedding and encryption. The H[$i$]dden framework offers perfect reversibility, highly scalable watermark capacity decoupled from the host data's range, and intrinsic data-watermark
entanglement. The paper further introduces two protocols: H[$i$]dden-EG, for joint reversible data hiding and encryption, and H[$i$]dden-AggP, for
privacy-preserving aggregation of watermarked data, based on partially homomorphic encryption. Rigorous comparative evaluation against recent state-of-the-art baselines demonstrates that the framework significantly expands
embedding capacity and achieves an exponential improvement in False Data Injection (FDI) resilience —ranging from $10^5$ to $10^{19}$ under standard configurations— effectively neutralizing targeted structural vulnerabilities such as homomorphic injection attacks. Furthermore, empirical performance analysis —encompassing hardware-agnostic cryptographic metrics and direct IoT edge hardware emulation (ESP32)— confirms the practical deployment feasibility of the framework within standard sensor duty cycles. Ultimately, these protocols provide efficient and resilient solutions for data integrity, provenance (or group-level integrity in the aggregated case), and confidentiality, serving as a foundation for new schemes based on the algebraic properties of the complex domain.work and application to dispersed data
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Cryptography and Security
You Have Been LaTeXpOsEd: A Systematic Analysis of Information Leakage in Preprint Archives Using Large Language Models
Richard A. Dubniczky, Bertalan Borsos, Tamas Bisztray et al. (+1 more)
The widespread use of preprint repositories such as arXiv has accelerated the communication of scientific results but also introduced overlooked security risks. Beyond PDFs, these platforms provide unrestricted access to original source materials, including LaTeX sources, auxiliary code, figures, and embedded comments. In the absence of sanitization, submissions may disclose sensitive information that adversaries can harvest using open-source intelligence. In this work, we present the first large-scale security audit of preprint archives, analyzing more than 1.2 TB of source data from 100,000 arXiv submissions. We introduce LaTeXpOsEd, a four-stage framework that integrates pattern matching, logical filtering, traditional harvesting techniques, and large
language models (LLMs) to uncover hidden disclosures within non-referenced files and LaTeX comments. To evaluate LLMs' secret-detection capabilities, we introduce LLMSec-DB, a
benchmark on which we tested 25 state-of-the-art models. Our analysis uncovered thousands of PII leaks, GPS-tagged EXIF files, publicly available Google Drive and Dropbox folders, editable private SharePoint links, exposed GitHub and Google credentials, and cloud API keys. We also uncovered confidential author communications, internal disagreements, and conference submission credentials, exposing information that poses serious reputational risks to both researchers and institutions. We urge the research community and repository operators to take immediate action to close these hidden security gaps. To support open science, we release all scripts and methods from this study but withhold sensitive findings that could be misused, in line with ethical principles. The source code and related material are available at the project website https://github.com/LaTeXpOsEd
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All authors Richard A. Dubniczky, Bertalan Borsos, Tamas Bisztray, Norbert Tihanyi
Cryptography and Security
Public-Key Encryption from the MinRank Problem
Rohit Chatterjee, Changrui Mu and Prashant Nalini Vasudevan
We construct a public-key encryption scheme from the hardness of the (planted) MinRank problem over uniformly random instances. This corresponds to the hardness of decoding random linear rank-metric codes. Existing constructions of public-key encryption from such problems require hardness for structured instances arising from the masking of efficiently decodable codes. Central to our construction is the development of a new notion of duality for rank-metric codes.
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Cryptography and Security
Securing Operating Systems Through Fine-grained Kernel Access Limitation for IoT Systems
Dongyang Zhan, Zhaofeng Yu, Xiangzhan Yu et al. (+3 more)
With the development of Internet of Things (IoT), it is gaining a lot of
attention. It is important to secure the embedded systems with low overhead. The Linux Seccomp is widely used by developers to secure the kernels by blocking the access of unused syscalls, which introduces less overhead. However, there are no systematic Seccomp configuration approaches for IoT applications without the help of developers. In addition, the existing Seccomp configuration approaches are coarse-grained, which cannot analyze and limit the syscall arguments. In this paper, a novel static dependent syscall analysis approach for embedded applications is proposed, which can obtain all of the possible dependent syscalls and the corresponding arguments of the target applications. So, a fine-grained kernel access limitation can be performed for the IoT applications. To this end, the mappings between dynamic library APIs and syscalls according with their arguments are built, by analyzing the control flow graphs and the data dependency relationships of the dynamic libraries. To the best of our knowledge, this is the first work to generate the fine-grained Seccomp profile for embedded applications.
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All authors Dongyang Zhan, Zhaofeng Yu, Xiangzhan Yu, Hongli Zhang, Lin Ye, Likun Liu
Cryptography and Security
Shrinking the Kernel Attack Surface Through Static and Dynamic Syscall Limitation
Dongyang Zhan, Zhaofeng Yu, Xiangzhan Yu et al. (+2 more)
Linux Seccomp is widely used by the program developers and the system maintainers to secure the operating systems, which can block unused syscalls for different applications and containers to shrink the attack surface of the operating systems. However, it is difficult to configure the whitelist of a container or application without the help of program developers. Docker containers block about only 50 syscalls by default, and lots of unblocked useless syscalls introduce a big kernel attack surface. To obtain the dependent syscalls, dynamic tracking is a straight-forward approach but it cannot get the full syscall list. Static analysis can construct an over-approximated syscall list, but the list contains many false positives. In this paper, a systematic dependent syscall analysis approach, sysverify, is proposed by combining static analysis and dynamic verification together to shrink the kernel attack surface. The semantic gap between the binary executables and syscalls is bridged by analyzing the binary and the source code, which builds the mapping between the library APIs and syscalls systematically. To further reduce the attack surface at best effort, we propose a dynamic verification approach to intercept and analyze the security of the invocations of indirect-call-related or rarely invoked syscalls with low overhead.
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All authors Dongyang Zhan, Zhaofeng Yu, Xiangzhan Yu, Hongli Zhang, Lin Ye
Cryptography and Security
Backdoor-Powered Prompt Injection Attacks Nullify Defense Methods
Yulin Chen, Haoran Li, Yuan Sui et al. (+2 more)
With the development of technology, large
language models (LLMs) have dominated the downstream natural
language processing (NLP) tasks. However, because of the LLMs' instruction-following abilities and inability to distinguish the instructions in the data content, such as web pages from search engines, the LLMs are vulnerable to
prompt injection attacks. These attacks trick the LLMs into deviating from the original input instruction and executing the attackers' target instruction. Recently, various instruction hierarchy defense strategies are proposed to effectively defend against
prompt injection attacks via fine-tuning. In this paper, we explore more vicious attacks that nullify the
prompt injection defense methods, even the instruction hierarchy:
backdoor-powered
prompt injection attacks, where the attackers utilize the
backdoor attack for
prompt injection attack purposes. Specifically, the attackers poison the supervised fine-tuning samples and insert the
backdoor into the model. Once the trigger is activated, the backdoored model executes the injected instruction surrounded by the trigger. We construct a
benchmark for comprehensive evaluation. Our experiments demonstrate that
backdoor-powered
prompt injection attacks are more harmful than previous
prompt injection attacks, nullifying existing
prompt injection defense methods, even the instruction hierarchy techniques.
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All authors Yulin Chen, Haoran Li, Yuan Sui, Yangqiu Song, Bryan Hooi
Cryptography and Security
A Time-Bound Signature Scheme for Blockchains
Benjamin Marsh and Paolo Serafino
We introduce a modified Schnorr signature scheme to allow for time-bound signatures for transaction fee auction bidding and smart contract purposes in a blockchain context, ensuring an honest producer can only validate a signature before a given block height. The immutable blockchain is used as a source of universal time for the signature scheme. We show the use of such a signature scheme leads to lower MEV revenue for builders. We then apply our time-bound signatures to Ethereum's EIP-1559 and show how it can be used to mitigate the effect of MEV on predicted
equilibrium strategies.
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Cryptography and Security · Cross-listed from cs.LG
From Theory to Practice: Evaluating Data Poisoning Attacks and Defenses in In-Context Learning on Social Media Health Discourse
Rabeya Amin Jhuma and Mostafa Mohaimen Akand Faisal
This study explored how in-context learning (ICL) in large
language models can be disrupted by data poisoning attacks in the setting of public health sentiment analysis. Using tweets of Human Metapneumovirus (HMPV), small
adversarial perturbations such as synonym replacement, negation insertion, and randomized perturbation were introduced into the support examples. Even these minor manipulations caused major disruptions, with sentiment labels flipping in up to 67% of cases. To address this, a Spectral Signature Defense was applied, which filtered out poisoned examples while keeping the data's meaning and sentiment intact. After defense, ICL accuracy remained steady at around 46.7%, and logistic regression validation reached 100% accuracy, showing that the defense successfully preserved the
dataset's integrity. Overall, the findings extend prior theoretical studies of ICL poisoning to a practical, high-stakes setting in public health discourse analysis, highlighting both the risks and potential defenses for robust LLM deployment. This study also highlights the fragility of ICL under attack and the value of spectral defenses in making AI systems more reliable for health-related social media monitoring.
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Cryptography and Security
QPADL: Post-Quantum Private Spectrum Access with Verified Location and DoS Resilience
Saleh Darzi, Saif Eddine Nouma, Kiarash Sedghighadikolaei et al. (+1 more)
With advances in wireless communication and growing spectrum scarcity, Spectrum Access Systems (SASs) offer an opportunistic solution but face significant security challenges. Regulations require disclosure of location coordinates and transmission details, exposing user
privacy and anonymity during spectrum queries, while the database operations themselves permit Denial-of-Service (DoS) attacks. As location-based services, SAS is also vulnerable to compromised or malicious users conducting spoofing attacks. These threats are further amplified given the advances in
quantum computing. Thus, we propose QPADL, the first post-
quantum (PQ) secure framework that simultaneously ensures
privacy, anonymity, location verification, and DoS resilience while maintaining efficiency for large-scale spectrum access systems. QPADL introduces SAS-tailored private information
retrieval for location
privacy, a PQ-variant of Tor for anonymity, and employs advanced signature constructions for location verification alongside client puzzle protocols and rate-limiting technique for DoS defense. We formally assess its security and conduct a comprehensive performance evaluation, incorporating GPU parallelization and optimization strategies to demonstrate practicality and scalability.
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All authors Saleh Darzi, Saif Eddine Nouma, Kiarash Sedghighadikolaei, Attila Altay
Cryptography and Security
On the Limits of Consensus under Dynamic Availability and Reconfiguration
Javier Nieto, Joachim Neu and Ling Ren
Proof-of-stake blockchains require consensus protocols that support Dynamic Availability and Reconfiguration (which we call the DAR model). Here, Dynamic Availability means that the consensus protocol should remain live even if a large number of nodes temporarily crash, and Reconfiguration means it should be possible to change the set of operating nodes over time. State-of-the-art protocols inspired by the DAR model, such as Ethereum, Cardano's Ouroboros, or Snow White, require additional model features comprising external mechanisms or node capabilities that are difficult to justify, such as social consensus or the requirement that key
evolution be performed even when nodes have crashed. The key result of this paper is the necessary and sufficient
adversarial condition under which consensus can be achieved in the plain DAR model, without any extra features. We then introduce an additional feature to the model that is justified by proof-of-stake blockchain designs: honest nodes complete a sign-off procedure the moment they express intent to exit from the set of operating nodes. This additional feature reduces the power of the adversary relative to the plain DAR model and helps us obtain a bootstrapping gadget that is particularly simple and efficient in the common optimistic case of few reconfigurations and no double spending.
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Cryptography and Security
Explainable but Vulnerable: Adversarial Attacks on XAI Explanation in Cybersecurity Applications
Maraz Mia and Mir Mehedi A. Pritom
Explainable Artificial Intelligence (XAI) has aided machine learning (ML) researchers with the power of scrutinizing the decisions of the black-box models. XAI methods enable looking deep inside the models' behavior, eventually generating explanations along with a perceived trust and transparency. However, depending on any specific XAI method, the level of trust can vary. It is evident that XAI methods can themselves be a victim of post-
adversarial attacks that manipulate the expected outcome from the explanation module. Among such attack tactics, fairwashing explanation (FE), manipulation explanation (ME), and
backdoor-enabled manipulation attacks (BD) are the notable ones. In this paper, we try to understand these
adversarial attack techniques, tactics, and procedures (TTPs) on explanation alteration and thus the effect on the model's decisions. We have explored a total of six different individual attack procedures on post-hoc explanation methods such as SHAP (SHapley Additive exPlanations), LIME (Local Interpretable Model-agnostic Explanation), and IG (Integrated Gradients), and investigated those
adversarial attacks in cybersecurity applications scenarios such as phishing, malware, intrusion, and fraudulent website detection. Our experimental study reveals the actual effectiveness of these attacks, thus providing an urgency for immediate
attention to enhance the resiliency of XAI methods and their applications.
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Cryptography and Security · Cross-listed from cs.AI
Cross-Modal Content Optimization for Steering Web Agent Preferences
Tanqiu Jiang, Min Bai, Nikolaos Pappas et al. (+2 more)
Vision-
language model (VLM)-based web
agents increasingly power high-stakes selection tasks like content recommendation or product ranking by combining
multimodal perception with preference
reasoning. Recent studies reveal that these
agents are vulnerable against attackers who can bias selection outcomes through preference manipulations using
adversarial pop-ups, image perturbations, or content tweaks. Existing work, however, either assumes strong white-box access, with limited single-modal perturbations, or uses impractical settings. In this paper, we demonstrate, for the first time, that joint exploitation of visual and textual channels yields significantly more powerful preference manipulations under realistic attacker capabilities. We introduce Cross-Modal Preference Steering (CPS) that jointly optimizes imperceptible modifications to an item's visual and natural
language descriptions, exploiting CLIP-transferable image perturbations and RLHF-induced linguistic biases to steer
agent decisions. In contrast to prior studies that assume gradient access, or control over webpages, or
agent memory, we adopt a realistic black-box threat setup: a non-privileged adversary can edit only their own listing's images and textual metadata, with no insight into the
agent's model internals. We evaluate CPS on
agents powered by state-of-the-art proprietary and open source VLMs including GPT-4.1, Qwen-2.5VL and Pixtral-Large on both movie selection and e-commerce tasks. Our results show that CPS is significantly more effective than leading baseline methods. For instance, our results show that CPS consistently outperforms baselines across all models while maintaining 70% lower detection rates, demonstrating both effectiveness and stealth. These findings highlight an urgent need for robust defenses as agentic systems play an increasingly consequential role in society.
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All authors Tanqiu Jiang, Min Bai, Nikolaos Pappas, Yanjun Qi, Sandesh Swamy
Cryptography and Security
PentestMCP: A Toolkit for Agentic Penetration Testing
Zachary Ezetta and Wu-chang Feng
Agentic AI is transforming security by automating many tasks being performed manually. While initial agentic approaches employed a monolithic architecture, the Model-Context-Protocol has now enabled a remote-procedure call (RPC) paradigm to agentic applications, allowing for the flexible construction and composition of multi-function
agents. This paper describes PentestMCP, a library of MCP server implementations that support agentic penetration testing. By supporting common penetration testing tasks such as network scanning, resource enumeration, service fingerprinting, vulnerability scanning, exploitation, and post-exploitation, PentestMCP allows a developer to customize multi-
agent workflows for performing penetration tests.
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