Cryptography and Security · Cross-listed from quant-ph
A Modular Approach to Succinct Arguments for QMA
James Bartusek, Jiahui Liu and Giulio Malavolta
Succinct argument systems are of central importance to modern crytpography, enabling the efficient verification of computational claims. In the classical setting, Kilian (STOC 92) established that any probabilistically checkable proof for NP can be transformed into a succinct argument system for NP using only collision-resistant hash functions. In the
quantum setting, recent works have established the feasibility of (classically-verifiable) succinct arguments for QMA, capturing statements that require *
quantum* proofs. However, known constructions all rely on the highly structured assumption of learning with errors (LWE), which stands in stark contrast with the unstructured assumptions that suffice for NP. In this work, we develop a new framework that broadens the cryptographic foundations of succinct arguments for QMA. We assume the existence of (i) an oblivious state preparation (OSP) protocol, which in turn can be constructed from *plain* trapdoor claw-free functions, and (ii) collapsing hash functions, the
quantum analogue of collision-resistance. In particular, we obtain the first succinct, classically-verifiable argument system for QMA which does not rely on the hardness of LWE. Our construction proceeds in two steps. First, we design a *round-efficient* classically-verifiable argument system for QMA based only on the assumption of OSP. Second, we introduce a *generalized communication compression compiler*, which, assuming collapsing hash functions, transforms any $T$-round interactive protocol into one in which the communication size is bounded by $T \cdot \poly(\secp)$ for some fixed $\poly$ independent of the original size of each message. Our compiler extends a
quantum rigidity-based communication compression technique of Zhang (QCrypt 25), and may be of independent interest.
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Cryptography and Security · Cross-listed from cs.LG
Toward Calibrated, Fair, and accurate Deepfake Detection
Ryan Brown and Chris Russell
Deepfake detectors show large performance gaps across demographic groups. Existing
fairness approaches require demographic labels, retraining, or sacrifice accuracy. We introduce Face-
Fairness (FF), a plug-and-play framework for bias mitigation. Our primary contribution, Face-Feature Tuning (FFT), is the first demographic label-free
fairness method demonstrated for deepfake detection: a lightweight calibrator that performs a logit remapping conditioned on frozen face
embeddings. We complement FFT with two variants: FF-Max, which maximizes worst-group accuracy when demographics are available, and FF-Discover, which does the same with
embedding-discovered groups. Across in-domain and cross-
dataset test settings, FF consistently reduces FPR/TPR gaps and improves minimum group accuracy while maintaining (often improving) overall accuracy. The approach is detector-agnostic, adds negligible runtime overhead, and requires no access to identity attributes.
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Cryptography and Security · Cross-listed from eess.SP
FADRW: A Feature-Aware Modulated and Dynamically Reweighted Loss for Few-Shot Linguistic Steganalysis
Shuo Liu, Xianghong Lin, Yukun Wei et al. (+1 more)
The ubiquity of social media platforms facilitates malicious linguistic steganography, posing significant security risks. However, detection is severely hampered by two fundamental issues during model training. Firstly, extreme class imbalance (less than 1% steganographic samples) induces a strong decision bias. Secondly, the invisibility of generative steganography means its features are nearly indistinguishable from benign text; this similarity, compounded by their extreme rarity, leads to severe feature marginalization, where faint steganographic signals are completely overwhelmed. To directly address these optimization-level challenges, we propose FADRW (Feature-Aware Modulated and Dynamically Reweighted Loss), a novel loss function framework engineered for few-shot steganalysis. FADRW employs Dynamic Reweighting to progressively counteract decision bias, and a Feature-Aware Modulation module to structurally reshape the feature space, preventing feature marginalization by enhancing the separability of these subtle features. Extensive experiments on
datasets from three real-world social platforms demonstrate that FADRW significantly outperforms state-of-the-art methods, particularly in the challenging few-shot steganographic sample scenario.
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All authors Shuo Liu, Xianghong Lin, Yukun Wei, Zhongliang Yang
Cryptography and Security
Bitcoin After Block Rewards
Junhyuk Lee
Bitcoin's block reward is scheduled to decline to zero, raising concerns about whether the network can remain secure once miners rely solely on transaction fees. This paper seeks to identify the conditions under which large-scale and persistent deviation from honest mining can arise. We analyze and compare the payoffs of honest and deviating miners in a sequential decision model, and identify a deviation threshold $G_t$ at which honest mining ceases to be privately optimal. Around the 2024 Bitcoin halving, we show that current mining behavior does not exhibit large-scale or structural deviation. However, when the block reward is removed, the $G_t$ criterion implies that deviation can arise even with a very small fraction of transaction fees. Finally, we evaluate three protocol-level mechanisms: Base Fee, Fee Floor, and an adaptive maximum block size rule, and show that their combination raises the deviation threshold and mitigates incentive breakdown in a fee-only regime. These results provide a practical
benchmark for assessing Bitcoin's security as block rewards disappear.
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Cryptography and Security
SHIELDS: Automating OS Hardening with Iterative Multi-Agent Remediation
Andrew Hamara, Dwight Horne, Aldehir Rojas et al. (+5 more)
Security misconfigurations remain a leading cause of OS-level compromise, and manually keeping systems compliant with standards like Defense Information Systems Agency (DISA) Security Technical Implementation Guides (STIGs) is a tedious and expensive process. Existing compliance automation tools can reduce some of this burden, but they depend on static, pre-written corrective actions. In this paper, we introduce SHIELDS, a multi-
agent system that uses large
language models (LLMs) to approach OS hardening as an iterative, feedback-driven process. Instead of applying fixed remediations, SHIELDS continuously proposes fixes and refines them based on feedback from target system execution and validation scans. We evaluate the system across multiple virtual machine configurations using six contemporary LLMs ranging from 20B to 400B parameters, and find that SHIELDS successfully remediates up to 73% of scan findings. Our results also suggest that success in this setting depends less on model size (parameter count) than on effective tool use and information gathering, paving a practical path toward reducing the burden of security compliance in environments where compute is limited or security and
privacy needs drive local model use.
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All authors Andrew Hamara, Dwight Horne, Aldehir Rojas, Timothy Kurniawan, Sophie Lamothe, Vishal Suresh, Nicholas Turoci, Lawrence Wong
Cryptography and Security
CRESS: Quantifying Vulnerabilities of Attack Scenarios in Hardware Reverse Engineering
Alexander Hepp, Matthias Ludwig, Michaela Brunner et al. (+2 more)
The safety, security, and reliability of microelectronic systems depend on a trustworthy, secured supply chain and design flow. Globally distributed supply chains or unintentional design weaknesses leave the door open for attacks on the hardware level. These scenarios encompass counterfeiting, hardware trojans, or on-device attacks. For these, hardware reverse engineering (RE) results play a pivotal role. The ongoing publication of new RE-involved attacks motivated the development of the common RE scoring system (CRESS). The system enables a general classification of RE-involved scenarios for a common, consistent rating. In this work, the originally qualitative system is extended to a quantitative system. We performed an extensive interview study with experts in the field. The interview results allowed us to derive weights that measure the severity of different RE-involved attack categories. The weights form an equation that quantifies scenarios, resulting in the severity-indicating CRESS score. The score enables the coherent rating of novel scenarios, renders them comparable, and supports the development of effective countermeasures. To showcase the effectiveness of the quantitative CRESS Score, six selected case studies are rated qualitatively and quantitatively. The CRESS Score proves to be significantly more expressive than the industry-standard Common Vulnerability Scoring System (CVSS).
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All authors Alexander Hepp, Matthias Ludwig, Michaela Brunner, Johanna Baehr, Georg Sigl
Cryptography and Security · Cross-listed from cs.LG
DP-MacAdam: Differentially Private Mechanism with Adaptive Clipping and Adaptive Momentum
Naima Tasnim, Lalitha Sankar and Oliver Kosut
Differentially private
stochastic gradient descent (DP-SGD) has become the standard framework for
privacy-preserving machine learning, yet its reliance on a fixed gradient clipping threshold to limit sensitivity remains a significant practical limitation. Adaptive clipping
algorithms such as AdaClip shift and scale the gradient prior to clipping and adding noise so that the clipped gradient yields a more informative descent direction. The shift and scaling parameters are selected adaptively based on the empirical mean and variance. However, in existing adaptive clipping
algorithms, these empirical estimates have not been also used for momentum to accelerate training itself. On the other hand, DP-Adam is an
algorithm that exploits Adam-like momentum updates based on the gradient mean and variance to accelerate training, but does not exploit these estimates for adaptive clipping. In this work, we propose Differentially Private Mechanism with Adaptive Clipping and Adaptive Momentum (DP-MacAdam), a novel
algorithm that combines these two approaches so as to use the same mean and variance estimates for both clipping and momentum. We perform an analysis showing that DP-MacAdam estimates the gradient variances in a bias-free manner. In addition, we empirically evaluate the
privacy and accuracy of DP-MacAdam, demonstrating that it achieves improved model utility compared to DP-SGD, AdaClip, and DP-Adam baselines, without requiring manual tuning of the clipping threshold.
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Cryptography and Security
Policy-Compliant Cloud Storage Systems
Dimitrios Stavrakakis, Masanori Misono, Julian Pritzi et al. (+3 more)
Privacy regulations such as the General Data Protection Regulation (GDPR) impose strict requirements on how personal data is stored, processed, and audited. While key-value stores (KVS) are widely used in latency-sensitive applications, their simple data model and untrusted cloud deployment environments make GDPR compliance particularly challenging. Existing approaches require invasive code modifications, impose high performance overheads, or overlook the integrity of compliance mechanisms themselves. This paper presents GDPRuler, a trusted middleware system that enables verifiable GDPR compliance for KVS on untrusted clouds without modifying their codebase. GDPRuler deploys a trusted GDPR monitor inside a Confidential Virtual Machine (CVM), which enforces GDPR policies, manages compliance metadata, and maintains tamper-evident audit logs. A declarative policy
language translates core GDPR obligations into enforceable runtime rules. To ensure efficiency, GDPRuler encodes metadata compactly within KV records, builds dedicated metadata indexes for GDPR-specific queries, and logs only compliance-relevant events in a space-efficient format. We implement GDPRuler as a transparent proxy for unmodified Redis and RocksDB deployments. Evaluation with YCSB and GDPR-inspired workloads shows that GDPRuler enforces core compliance guarantees with low overheads: GDPRuler achieves ~61% of native KVS throughput with the CVM environment contributing 28%-32% of it, metadata storage overhead remains below 20%, and GDPR queries benefit from 13-182x speedup through metadata indexing. By
embedding verifiable policy enforcement into a trusted middleware layer, GDPRuler offers a practical path toward GDPR-compliant KVS on untrusted cloud infrastructures.
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All authors Dimitrios Stavrakakis, Masanori Misono, Julian Pritzi, Harshavardhan Unnibhavi, Nuno Santos, Pramod Bhatotia
Cryptography and Security
A formal framework for the economic security of DeFi compositions
Massimo Bartoletti, Riccado Marchesin and Roberto Zunino
Decentralized Finance (DeFi) services are usually constructed by composing a variety of smart contracts. While composability is a key driver of the success of DeFi, it also creates security risks: adversaries may exploit interactions between newly deployed contracts and the pre-existing ones to inflict economic losses. We introduce MEV non-interference, a formal security notion for DeFi composability requiring that the maximal extractable value from a set of newly deployed contracts is not increased by interactions with the existing blockchain state. To support this notion, we define local MEV, a novel measure of economic attacks that focusses on the loss of a given set of victim contracts. We study two
adversarial models, with bounded and unbounded wealth, and establish sufficient conditions and locality principles that enable modular
reasoning about secure composability. We apply the framework to representative DeFi compositions, including exchanges, AMMs, options, lending pools, routers, and arbitrage contracts, showing how it distinguishes secure compositions from vulnerable ones. Our results provide a formal foundation for
reasoning about the economic security of DeFi compositions.
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Cryptography and Security
Willing but Unable: Separating Refusal from Capability in Code LLMs via Abliteration
Cristina Carleo, Pietro Liguori, Naghmeh Ivaki et al. (+1 more)
Producing a labeled vulnerable code at scale is a recurring obstacle for learning-based vulnerability detection: mined corpora carry substantial label noise, and existing LLM-based augmentation propagates these inaccuracies because it transforms vulnerable seeds rather than synthesising vulnerabilities from a specification. A complementary route is to start from safe code and ask an instruction-tuned LLM to inject a specified CWE (which would shift the labeling burden from open-ended detection to bounded binary confirmation) but safety-aligned code LLMs systematically refuse such
prompts. This paper is a preliminary feasibility study of abliteration, a low-rank weight edit that orthogonally projects out the refusal direction in the residual stream, as a tool to remove this barrier. We use Python and CWE-89 (SQL injection) as a case study, evaluating the Qwen2.5-Coder-Instruct family at 3B, 7B, and 14B parameters on safe samples drawn from PromSec and SafeCoder, replicated three times per condition. We find that (i) refusal on injection
prompts is strongly size- and
prompt-context-dependent: the 14B refuses 100% of
prompts, the 7B refuses 73% of PromSec but only 5% of SafeCoder, whereas the 3B is essentially never blocked; (ii) abliteration reduces refusal to zero or near-zero across all sizes while leaving syntactic validity above 93%, supporting the view that, in this setting, refusal can be detached from measured code-generation capability; and (iii) the post-abliteration injection rate remains capacity-bound (88-97% on the 14B, 89-90% on the 7B, and 25-48% on the 3B) separating willingness, which abliteration unlocks, from capability, which scales with parameters. Vulnerability verdicts are produced by a three-tool detector ensemble (CodeQL, Semgrep, Bandit) followed by manual adjudication by two authors on detector-positive outputs.
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All authors Cristina Carleo, Pietro Liguori, Naghmeh Ivaki, Domenico Cotroneo
Cryptography and Security · Cross-listed from cs.CY
Online Safety Regulation Increases Attention to VPNs: Privacy Implications of the UK Online Safety Act
Dhyey Mehta, Eldar Jalilzade, Maksim Kalameyets et al. (+5 more)
Governments worldwide are increasingly regulating digital platforms to reduce online harms, but access restrictions can alter user behaviour and create new
privacy risks. The UK Online Safety Act, passed in 2023, rolled out in phases - illegal-content enforcement in March 2025 and mandatory age verification in July 2025. We analyse Reddit discourse across VPN and UK Politics communities and conduct a
privacy-policy risk analysis of 69 VPN services. We find that the behavioural response is concentrated at the July 2025 deadline, when platforms hosting pornographic content were required to deploy age checks. UK VPN search interest on Google increased by 147% at this deadline. UK-resident users' VPN-subreddit activity increased by 145%. Their regulatory- or
privacy-related VPN posts and comments rose by 1,265% at this deadline. UK Politics communities show the same concentration at a larger magnitude, with OSA-related political discourse rising by 1481%. These effects were far smaller or statistically indistinguishable from pre-existing trends at Royal Assent and the illegal-harms enforcement deadline, indicating that the deployed age checks drove the response. Users primarily frame this response around
privacy, surveillance, and distrust of age-verification intermediaries rather than access-seeking, with near-zero genuine pro-OSA sentiment across two independent classifiers. Several users noted that those least able to pay for reputable VPNs are most likely to turn to free services that monetise their data. Search
attention increases across all disclosed
privacy-risk categories, with no evidence of a shift toward higher-risk VPN providers. Crucially, after a full year, this
attention is still elevated, arguing against a temporary news-cycle reaction. Thus, online safety regulation may create secondary
privacy costs without disproportionately directing
attention toward higher-risk VPNs.
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All authors Dhyey Mehta, Eldar Jalilzade, Maksim Kalameyets, Rebecca Owens, Marc Juarez, Stergios Aidinlis, Lei Shi, Tuğrulcan Elmas
Cryptography and Security
From Attack Simulation to SIEM Rule: Deterministic Detection-as-Code Synthesis with Probe-Level Traceability
Alexandre Cristovão Maiorano
Security teams routinely simulate attacks against their own systems to check whether their monitoring would catch a real intruder. These Breach-and-Attack-Simulation (BAS) tools surface findings, but the security information and event management (SIEM) systems that watch production need detection rules – and today a human bridges that gap by hand, reading each finding and writing the corresponding Sigma rule (a vendor-neutral detection format). We show this translation can be partially automated when probes are drawn from a locked corpus, so each finding carries a stable identifier back to the originating probe. We describe a deterministic synthesis function that maps each finding to a starter Sigma rule through a small template library (N=23, indexed by categories from the OWASP LLM and Web Top 10), with a back-reference to the originating finding and its MITRE ATT&CK technique. On two locked corpora (17-probe LLM, 23-probe Web), every bypassed-probe finding yields a starter rule, and all 17/17 emitted rules parse and convert to Splunk and Elasticsearch backends. Replayed through a live OpenSearch SIEM, the LLM rules fire on 30% of a held-out AdvBench subset and 14% of HarmBench at 7.7% false positives on a benign baseline; the Web side is validated structurally, not against a held-out attack set. The contribution is a verifiable, byte-stable path from BAS finding to operator-deployable starter rule, re-derivable from the published corpus and template library alone – trading the breadth of LLM-generative methods for exact reproducibility and a typed traceback from any fired alert to the originating probe.
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Cryptography and Security
Search-Time Contamination in Deep Research Agents: Measuring Performance Inflation in Public Benchmark Evaluation
Yongjie Wang, Xinyue Zhang, Kunhong Yao et al. (+4 more)
Public
benchmarks enable fair and reproducible evaluation of LLM
reasoning, but they become fragile for deep research
agents that actively search the web during inference. Such
agents may retrieve public
benchmark metadata, question context, or even ground-truth answers via web search. This gives rise to Search-Time Contamination (STC), where external
retrieval bypasses intended
reasoning and inflates measured performance. We systematically study STC in deep research
agent evaluation. We define three contamination types with increasing severity, namely
Benchmark Metadata Leakage, Question-Context Leakage, and Explicit Answer Leakage, and develop detection
algorithms to identify them and quantify their impact on
agent performance. Evaluating modern deep research
agents on six public
benchmarks, we find that STC is widespread and can inflate performance by up to 4%. Our findings show that existing evaluations may overestimate true
reasoning ability. We therefore advocate contamination-aware practices, including isolated sandboxes, transparent search trajectories, and controlled
benchmark access.
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All authors Yongjie Wang, Xinyue Zhang, Kunhong Yao, Zhiwei Zeng, Kaisong Song, Jun Lin, Zhiqi Shen
Cryptography and Security
Domain-Conditioned Safety in Frontier Computer-Using Agents: A 793-Episode Browser Benchmark, a Coding-Domain Cross-Reference, and a Reproducibility Audit of Recent Red-Teaming
Nicholas Saban
Recent computer-using-
agent (CUA) red-teaming papers report
prompt-injection attack success rates (ASR) of 42-98%, but these headline numbers cluster on retired models and on the most-vulnerable model in each paper's panel. We ask whether those techniques, reproduced as hand-crafted templates, still work against current frontier CUAs. We release CUA-HandCrafted, a public
benchmark of 793 episodes spanning 24 multi-step web tasks, 56 attack templates, 8 attack families, and 4 system-
prompt configurations. Against Claude Sonnet 4.6 and GPT-5.4 we measure 0/140 multi-step attack success (Clopper-Pearson 95% upper bound 2.60%); a
prompt ablation shows this resistance lives in the model weights. Yet it does not generalize: on a sister coding-
agent benchmark (SkillBench), the same weights fall to hand-crafted skill-injection at up to 100%. We argue that the literature's high ASR is largely attributable to RL-optimized injection text rather than the attack categories, and that frontier safety hardening is domain-conditioned, specific to the heavily-targeted browser surface. Reporting techniques without releasing the optimized strings, or extrapolating browser-domain safety to other CUA modalities, makes published ASR numbers unreproducible.
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Cryptography and Security
Preserving Data Privacy in Learning Causal Structure with Fully Homomorphic Encryption
Jian Yang, Yuan Tong, Qinbin Li et al. (+2 more)
Preserving data
privacy is an important topic in structural data management and data mining. However, the issue of
privacy leakage in distributed causal structure learning is a persistent challenge, especially in cases where data transmission and computation are required. In this paper, we propose a method based on fully homomorphic encryption (FHE) that performs calculations on ciphertexts, keeping data encrypted in transition and computation. Nevertheless, adopting FHE to causal structure learning is challenging due to the high computation cost and limited support on division as well as logarithm operations in FHE. To tackle this challenge, we propose a series of novel techniques including (i)
circuit simplification for better efficiency, (ii) approximation of division and logarithm through Newton-Raphson Reciprocal and Taylor expansion, and (iii) a batching technique with SIMD-acceleration to enhance the whole learning process. Additionally, our method can be easily extended beyond FHE by demonstration of its portability to support differential
privacy. Empirical results show that our method achieves high consistency and comparable causal structure with the plaintext version in the
datasets tested. Last, our method is efficient and practical to complete learning causal structures in tens of minutes even under the
privacy protection of FHE.
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All authors Jian Yang, Yuan Tong, Qinbin Li, Zeyi Wen, Xiaofang Zhou
Cryptography and Security
A-Live: Passive Liveness Detection via Neuromuscular Micro-Motion Signatures on Commodity Sensors
Mohammed Gharib, Sam Burns and Martin Zizi
Liveness detection has evolved from a safeguard against presentation and replay attacks in biometric authentication to a broader requirement for distinguishing human users from non-human
agents in modern digital systems. The emergence of generative and agentic AI further amplifies this need, positioning liveness as a fundamental security primitive. Existing approaches face key limitations, including reliance on explicit user interaction, specialized hardware, vulnerability to increasingly realistic spoofing, and limited scalability in real-world deployments. We present A-Live, a passive liveness detection framework that operates solely on inertial measurement unit (IMU) signals available in commodity devices. A-Live is based on the observation that neuromuscular micro-motions inherent to human motor control produce subtle but measurable signatures in inertial data, which are often treated as noise in prior work. We design a lightweight feature extraction pipeline and a compact classifier suitable for real-time on-device deployment, and introduce a controllable physical micro-motion platform to evaluate robustness against engineered non-human motion. Extensive evaluation across Android and iOS devices, including both automated and real-user settings, shows that A-Live achieves over 99.5% accuracy with low false acceptance and rejection rates. Our results demonstrate that neuromuscular micro-motion signatures provide a scalable and passive foundation for liveness detection under emerging AI-driven threat models.
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Cryptography and Security
Bernoulli CUSUM and Bayes-Optimal Detection Ceilings for Trust Fraud in Sparse Rating Networks
Talal Ashraf Butt
Sequential trust detection in rating networks relies on continuous observation models that fail on real data. On Bitcoin-OTC, 56% of ratings take a single value under standard mapping, breaking the distributional assumptions that parametric detectors require. This paper makes three contributions. It derives a Bayes-optimal F1 detection ceiling for per-node sequential detectors using empirically measured observation parameters. At Bitcoin-OTC's median in-degree of 2, this ceiling falls to 0.451 for strategic attacks, explaining why unsupervised methods cluster near $F1 \approx 0.4$. The analysis shows that detector-model matching, not information content, determines performance: binary models retain 86% of mutual information while enabling exact parametric fit. A dual-regime architecture is presented where Bernoulli CUSUM detects behavioral shifts and triggers asymmetric scoring. Ablation reveals a co-design constraint: the modulation mechanism improves AUC by 0.030 on binary observations but degrades it by 0.094 on continuous observations. The combined system achieves AUC 0.749 on Bitcoin-OTC and 0.796 on Bitcoin-Alpha, beating GaaSTrust on all 8 attacks ($p < 0.003$), with founder-label AUC of 0.999.
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Cryptography and Security
Attention-Augmented LSTMs for Automatic Homophonic Ciphertext Decipherment
Micaella Bruton, Meriem Beloucif and Beáta Megyesi
Homophonic substitution ciphers replace each plaintext letter with one of several possible ciphertext codes, deliberately weakening letter-frequency patterns and making automated decipherment difficult. This paper evaluates whether an
attention-augmented Long Short-Term
Memory (LSTM) model can learn such mappings in a historically motivated shared-key setting: all ciphertexts draw from the same known homophonic code pool, while individual keys use different consistent subsets of that pool. Using synthetic ciphertexts generated with ChronoFidelius from historical English and Swedish texts dated 1500–1899, we test performance across ciphertext lengths, centuries, variable-length codes, and simulated transcription errors. Models are trained only on aligned ciphertext–plaintext pairs, without external
language models, frequency statistics, or key-search heuristics. Results show near-perfect character-level decryption accuracy across both
languages and all periods, including short and noisy ciphertexts. The model also fails predictably on ciphertexts outside the shared pool, indicating that it functions as a practical tool for decipherment and key-space verification when key reuse is suspected.
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Cryptography and Security
SharedRequest: Privacy-Preserving Model-Agnostic Inference for Large Language Models
Peihua Mai, Xuanrong Gao, Youlong Ding et al. (+3 more)
With the widespread deployment of public large
language models (LLMs) such as ChatGPT, protecting user
prompt privacy has become an increasingly critical issue. Existing
privacy-preserving inference methods sacrifice either utility or efficiency, and often require model-specific modifications that limit their compatibility. In this paper, we propose SharedRequest, a model-agnostic framework for
privacy-preserving LLM inference that reformulates
privacy protection at the batch level rather than the individual-
prompt level. The key idea is to obscure sensitive information by mixing original
prompts with noisy variants, while grouping semantically equivalent instructions to amortize the inference cost over a large batch of queries with minimal impact on LLM response quality. This design is independent of the LLM architecture, requiring no access to model parameters or architectural modification. Empirical results demonstrate that SharedRequest achieves over $20\%$ higher utility compared to prior differential
privacy baselines, and its shared-
prompt mechanism reduces query cost by up to $5\times$ compared to non-batched inference.
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All authors Peihua Mai, Xuanrong Gao, Youlong Ding, Xianglong Du, Wei Liu, Yan Pang
Cryptography and Security
From Agent Traces to Trust: A Survey of Evidence Tracing and Execution Provenance in LLM Agents
Yiqi Wang, Jiaqi Zhang, Zhangkai Wu et al. (+8 more)
Large
language model (LLM)-based
agents are moving beyond text generation to planning, tool use,
retrieval,
memory access, environmental interaction, and multi-
agent collaboration. Because their outputs depend on information and execution steps across an
agent run, their execution processes are difficult to verify, debug, and audit. Even a correct final answer does not reveal which evidence supported its claims, whether tool calls were justified, how
memory shaped decisions, or where execution failures originated. Relevant research addresses these questions across evidence attribution, tool-use safety,
agent memory, and observability, but these areas emphasize different parts of the execution process. This survey brings them into a common framework through execution provenance, a typed graph of an
agent run, and evidence tracing, its projection onto evidence-support relations, distinguishing evidence that supports a conclusion from execution that influences it. We introduce a six-dimensional taxonomy covering trace sources, evidence and execution units, provenance relations, tracing granularity and timing, representation forms, and trust functions, complemented by operational definitions of nine provenance relations and two cross-cutting attributes, provenance origin and trace assurance. Applying this framework to the surveyed systems and
benchmarks reveals three gaps: limited integration of fine-grained provenance with multiple trust functions, no
benchmark in our catalog that evaluates the complete provenance chain, and little reporting of tamper-evident or attested traces. These findings motivate research on unified trace schemas, semantic provenance,
memory and multi-
agent lineage, provenance-aware safety and recovery, realistic
benchmarks, trace assurance, and
privacy-aware
auditing. Resources are available at https://github.com/xiaoqi-7/
Agent-Tracing-Survey.
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All authors Yiqi Wang, Jiaqi Zhang, Zhangkai Wu, Taotao Cai, Zirui Liu, Zequn Sun, Mingkai Zheng, Manqing Dong, Yu-Xuan Qiu, Xuefei Yin, Yanming Zhu