Cryptography and Security
Cancerous Backdoor Attack: Gradual Activation via Invisible Tokens and A Stage Controller
Tahmid Imtiaz Imu, Emama Nahid, Prodipta Sen Amartya et al. (+5 more)
Backdoor Attacks on Large
Language Models (LLMs) typically follow a trigger-response pattern, where satisfying a trigger condition activates a single terminal behavior. However, this single-point backdoor activation does not explore attacks in which malicious behavior develops gradually through multiple intermediate stages before reaching the terminal activation stage. We present Cancerous Backdoor Attack, that gradually corrupts an LLM's
reasoning over a sequence of interactions by leveraging invisible
tokens and a stage controller. Specifically, invisible
tokens provide hidden stages to the model without appearing in the user's visible request and the stage controller tracks the attack's progression during inference to realize gradual activation. We evaluate Cancerous Backdoor Attack across several
reasoning datasets. The attack consistently produces gradual
reasoning corruption across models and tasks. We compare Cancerous Backdoor Attack with prior backdoor attack baselines to demonstrate our proposed attack outperforms the baselines. Our results indicate that
reasoning corruption can develop gradually before it becomes visible, making answer accuracy alone insufficient for detecting backdoor attacks.
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All authors Tahmid Imtiaz Imu, Emama Nahid, Prodipta Sen Amartya, Ahsanul Jobayer, Yutong Song, Jiang Wu, Pengfei Zhang, Honghui Xu
Cryptography and Security
HOMARD: Hammering Off-chip Memory via Aggregate power Rail Disclosure
Eliott Quéré, Li-Chung Chiang, Carina Fiedler et al. (+6 more)
Software-based microarchitectural attacks have mainly exploited timing differences to infer information from DRAM. However, defenses and optimizations can prevent timing-based approaches from resolving precise microarchitectural behaviors. We show that unprivileged millisecond- and milliampere-resolution power sensors on modern Arm SoCs can recover DRAM mapping functions and reveal the data dependence of
memory accesses without timers. We present HOMARD, a methodology that reads DRAM activity from this telemetry, and two attack primitives. HOMARD-RE is a hierarchy-aware linear-algebraic method that reverse-engineers DRAM addressing functions from power alone. HOMARD-DATA recovers the Hamming weight of a fetched cache line through joint-power rail templating and secret byte values through correlation power analysis on the same rails. Across an AMD ZCU102, a Raspberry Pi 5, and a multi-chip-based LPDDR4 NVIDIA Jetson TX2, HOMARD-RE succeeds where row-buffer timing methods fail. On the Pi 5, HOMARD-DATA classifies 9 Hamming-weight levels at 81.5% accuracy and recovers secret bytes in minutes by correlating rail current with data-dependent bit toggling between neighbors in a row. Both primitives work with an architectural load or a mispredicted Spectre-RSB path on which no value is architecturally read. These results establish unprivileged power telemetry as an independent side channel for profiled microarchitectural attacks, particularly when timing falls silent.
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All authors Eliott Quéré, Li-Chung Chiang, Carina Fiedler, Thomas Rokicki, Maria Méndez Real, Alessandro Palumbo, Lilian Bossuet, Rubén Salvador, Daniel Gruss
Cryptography and Security
Organizational Context for the Enterprise Security Brain
Eden Yavin, Ariel Zadok, Gal Engelberg et al. (+2 more)
Agents that investigate and decide on enterprise security reason over a machine-readable view of the environment: its assets, identities, configurations, relations, and findings. The correct judgment about an asset also depends on what the organization knows about it: who owns it, what business function it serves, which policy governs it, and which risks were accepted. Part of this knowledge can be inferred from machine state, such as an ownership tag; most of it is recorded by people in policies, audit reports, architecture diagrams, tickets, and conversations, outside machine state. We call this distance the organizational context gap. Closing it poses four challenges: extracting the right claims from heterogeneous organizational data and, at inference time, detecting claims made stale by live state, checking live state against the governing policy, and binding architecture diagrams, which carry the business logic, to live resources. We introduce organizational context as a layer of the enterprise security
brain and define it with a taxonomy and six properties its representation must preserve. We then define a context model in which a claim carries one meaning, an attestation records each source that asserts it, strength is derived from live evidence at read time, and claims resolve onto the entities of the asset graph. On a production environment spanning AWS, Okta, Google Workspace, and GitHub, extraction recovers 0.80 of a pooled 1,355-claim ground truth at 0.87 precision, with 0.5% of extracted claims unsupported by their source. An
agent reasoning over live state and resolved context raises the conflict in 0.97 of stale-finding tasks, and reaches answer correctness of 0.83 on policy-
alignment tasks and 0.86 on architecture tasks.
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All authors Eden Yavin, Ariel Zadok, Gal Engelberg, Elad Elouz, Leon Goldberg
Cryptography and Security
SoK: Privacy-Preserving Order Matching
Prerna Arote, Adrian Saiz and Lucianna Kiffer
Privacy-preserving order matching enables traders to discover and execute compatible orders while limiting disclosure of sensitive trading information. Existing systems span financial
markets and blockchain-based asset exchanges and employ diverse
market structures,
privacy mechanisms, and trust assumptions, making their
privacy guarantees difficult to compare. We present a systematization of
privacy-preserving order matching covering 22 protocol families. We organize the order lifecycle into four phases: order representation and submission, order discovery and collection, order-matching, and settlement, and characterize each phase by protected and exposed information, access roles,
privacy mechanisms, and trust assumptions. Our analysis shows that
privacy is not a single protocol-level property: protecting selected order attributes or individual phases does not necessarily prevent leakage elsewhere in the lifecycle. We identify recurring trade-offs among
privacy, functionality, trust, and verifiability, highlighting the challenge of achieving end-to-end
privacy across the complete order lifecycle.
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Cryptography and Security
An Exploration of Attacks on AI Agent Systems
Cathleen Qiao, Layah Vigneaud, Chloe Brandon et al. (+9 more)
As autonomous AI
agents become more integrated into sensitive domains, it is crucial that single and multi-
agent AI systems are secured. This paper investigates how
prompt injection attacks can exploit both direct user inputs and inter?
agent communication to leak sensitive information and trigger cross-
agent infections. While our tests mostly highlight key vulnerabilities in single-
agent systems, we also extend these attacks to multi-
agent frameworks, investigating how weaknesses can propagate across
agents. Our findings emphasize the need for more robust defenses as AI
agents become more commonly embedded in real-world workflows.
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All authors Cathleen Qiao, Layah Vigneaud, Chloe Brandon, Max Cabilangan, Xiyuan Cao, Isaac Khabra, Reva Mahajan, Lena Nguyen, Kyle Pak, Anagh Pandya, Roshni Dave, Peiran Wang
Cryptography and Security
From Reactive Containment to Proactive Assurance: Lessons from OpenAI, Anthropic, and Google Agent Security Incidents
Abbas Raftari
In 2026, cybersecurity evaluations involving OpenAI, Anthropic, and Google
agents reached real systems outside their authorized test scope. The paths were different. OpenAI
agents exploited research infrastructure, coordinated across runs, and compromised parts of Hugging Face's production environment. Anthropic reported cases in which a misconfigured third-party environment exposed real systems to
agents pursuing simulated cyber tasks. In a separately reported evaluation, Google's Gemini accessed three real organizations through an unintended internet route; Google stated that the model stopped in all three instances. Taken together, the cases show why an evaluation cannot rely on an assumed boundary. That boundary must be verified while the
agent is operating. This comparative instrumental case study develops a Proactive
Agent Security Assurance Cycle (PASAC) and a five-layer Boundary Assurance Stack. The framework combines risk-tiered task design, executable scope contracts, pre-run validation, least-capability access, independent egress enforcement, credential restrictions, cross-run monitoring, automatic stop conditions, and evidence-based reauthorization. A leading-indicator model, nine design propositions, and seven falsifiable hypotheses turn these lessons into a testable research program. Because the public Gemini record is limited to attributed statements and journalism, its detailed causal mechanism remains provisional. The central conclusion is straightforward: proactive
agent security requires continuous assurance across the full execution system, not confidence in any single sandbox or safeguard.
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Cryptography and Security
ORCAGen: Orchestrating Context-Aware Malware Deception with RAG-Guided Generative AI
Shihab Ahmed, Md Sajidul Islam Sajid, Teryl Taylor et al. (+2 more)
Malware defenses often remove or isolate suspicious programs as quickly as possible. While effective for containment, this approach can also waste an opportunity to observe attacker behavior and deploy targeted countermeasures. ORCAGen takes a different approach: it uses GenAI to build malware-specific deception playbooks offline, validates them before deployment, and enforces only the verified logic at runtime. ORCAGen combines
Retrieval-Augmented Generation (RAG) with structured
prompt engineering to generate both proof-of-concept (PoC) malware and corresponding deception orchestration code. A curated knowledge base (KB) of malware procedures and active defense strategies grounds the generation process, helping the LLM produce threat-specific and executable deception logic rather than generic or hallucinated outputs. The generated PoC malware provides a safe and reproducible way to test whether a deception strategy can disrupt, redirect, or suppress targeted malware behavior before the strategy is added to the runtime playbook. We evaluate ORCAGen across GPT-4o, GPT-5.5, Gemini 3.5 Flash, Qwen3-Coder, and Claude Sonnet 4.5 using execution success,
hallucination rate, refinement effort, deception effectiveness, and runtime overhead. The evaluation covers synthesized malware scenarios and 150 real-world malware samples across keyloggers, information stealers, and ransomware. Across the evaluated scenarios, GPT-5.5 required the fewest refinements and produced no observed hallucinated APIs, while Gemini 3.5 Flash achieved the lowest response time and runtime overhead. The results show that RAG-guided structured prompting can support the scalable construction of malware-specific deception playbooks that remain lightweight and deterministic during runtime enforcement.
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All authors Shihab Ahmed, Md Sajidul Islam Sajid, Teryl Taylor, Frederico Araujo, Tariqul Islam
Cryptography and Security · Cross-listed from quant-ph
Improved Local Leakage Resilience of Shamir Secret Sharing and Worst-Case Optimal Polynomial Intersection
Yihang Sun and Mary Wootters
We study two problems: Local Leakage Resilience (LLR) for Shamir secret sharing, and worst-case Optimal
Polynomial Intersection (OPI). Both problems concern
polynomials $Q(X)$ of degree less than $k$, over a
prime-order finite field $\mathbb{F}_p$. In LLR for Shamir secret sharing, one asks how much one can learn about $Q(0)$ given a few bits leaked from each of $Q(\alpha_1), \ldots, Q(\alpha_n)$, for distinct non-zero evaluation points $\alpha_i \in \mathbb{F}_p$. In OPI, one is given input list $S_1, \ldots, S_n \subset \mathbb{F}_p$, and wants to find a
polynomial $Q(X)$ of degree less than $k$ so that $Q(\alpha_i) \in S_i$ for as many $i$ as possible. Leveraging recent connection between these two problems due to (Sun, Wootters 2026), we improve the state-of-the-art for both problems. For LLR, we show that there is some constant $\delta > 0$ so that, as long as $R := k/n \geq 1/2 - \delta$, Shamir secret-sharing is one-bit locally leakage resilient (meaning that one can learn only a negligible amount about $Q(0)$). This is the first result to break the so-called "one-half barrier" for LLR, and improves over the previous best known result, requiring $R \geq 0.668$ (Kasser, 2025). For OPI, we give a
quantum algorithm that finds a
polynomial $Q(X)$ that agrees with at least a $\mathsf{SCL}_\rho(R)-\varepsilon$ fraction of the lists in expectation, for every fixed $\varepsilon>0$, where $\mathsf{SCL}_\rho$ is the semicircle law of (Jordan et al., 2025). This improves previous algorithmic (and existential) results of (Jo, 2026) and (Horinaga, Yamakawa, 2026). We also give further improved existential results. We also adapt the hardness result of (Yamakawa, Zhandry, 2024) to apply to OPI (rather than a folded version); over large fields, this gives an unconditional separation between the
quantum and classical hardness of OPI relative to a membership oracle.
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Cryptography and Security
ReSI: Recursive Safety Improvement toward Resistant and Resilient AI
Jingnan Zheng, Dongcheng Zhang, Yi Zhang et al. (+10 more)
Recursive self-improvement, the participation of AI systems in improving their own capabilities, is beginning to move from theoretical prospect to practice, posing both challenges and opportunities for safety
alignment. Models evolve through frequent updates, and their safety
alignment requires continual adaptation to each new checkpoint. Meanwhile, with evolving red-teaming methods exposing new vulnerabilities, safety improvement for each checkpoint needs to mitigate exposed vulnerabilities and generalize to risks not yet revealed. Following R$^2$AI, we term these goals resistance to known threats and resilience to unforeseen risks. Recursive self-improvement, in turn, inspires an approach to both goals: safety
alignment could likewise advance through successive rounds of evaluation and update. We therefore introduce ReSI, a recursive safety improvement framework that implements this approach through automated research. In each round, ReSI applies diverse red-teaming methods to identify vulnerabilities in the current target model, develops training recipes, and promotes the update with the largest safety gain among those passing a Pareto gate on capability retention as the next target model. Across four dense and mixture-of-experts models, ReSI matches or exceeds evaluated frontier models on in-distribution and out-of-distribution safety
benchmarks, and outperforms
alignment baselines on nearly all safety evaluations while largely preserving general capabilities. In particular, ReSI reduces the mean X-Teaming attack success rate across the four models from 86.01% to 31.45%, well below GPT-5.6-Luna's leading frontier result of 56.69%, indicating stronger resilience to attacks unseen during training. These findings support recursive safety improvement as a practical path toward resistant and resilient AI.
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All authors Jingnan Zheng, Dongcheng Zhang, Yi Zhang, Ming Zhang, Qiaosheng Zhang, Youbang Sun, An Zhang, Xiangnan He, Tat-Seng Chua, Xia Hu, Bowen Zhou, Chaochao Lu, Xiang Wang
Cryptography and Security
One Node, Two Roles: Simultaneous Contests for Validation and Attention in Rollups
Pranay Anchuri, Ben Berger, Matteo Campanelli et al. (+1 more)
An optimistic rollup is safe as long as at least one honest validator executes its state transition function (STF) and disputes any assertion that is inconsistent with the result of the execution. Allowing anyone to participate, however, does not give incentive to do so: as long as every assertion is correct, verifying assertion correctness goes unpaid.
Attention mechanisms address this by paying nodes to execute the rollup's STF, regardless of whether they participate in the validation process. Since a single node operator can back many registered identities with a single execution, paying per identity does not buy execution diversity, that is, the number of operators that independently execute. In this work we provide a new modeling framework for this problem. We formalize the underlying cryptographic primitive as a new notion, arguments with registered provers, whose properties include a form of non-amortizability that, to our knowledge, has not been studied for modern succinct cryptographic proofs before. We design validation and
attention reward mechanisms and analyze them as two coupled Tullock-like contests, in which an operator pays once for the required execution and then chooses how many identities to deploy in each role. We quantify the attainable range of execution diversities in
equilibrium as a function of the marginal cost of deploying an extra
attention identity. We use our framework as a lens through which we compare two
attention mechanisms, TRACE (MARBLE 2026) and Proof of Diligence (AFT 2024). In particular, we show that as opposed to Proof of Diligence, in TRACE the marginal cost mentioned above can be adjusted to support a higher execution diversity. As a case study, we apply our results to Arbitrum One, a widely deployed optimistic rollup.
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All authors Pranay Anchuri, Ben Berger, Matteo Campanelli, Akaki Mamageishvili
Cryptography and Security · Cross-listed from cs.LG
Verification with Transfer: Exact Information Frontiers and Their Price in Calls
Hazar Yueksel
A verifier that accepts or rejects whole answers reveals little: under a flat prior over $k$-bit answers, zero error needs $2^k-1$ verifications. The usual remedy is to solve related source tasks, either all first, as a curriculum does, or interleaved with verification. We price this remedy in information and in calls. With an exact verifier, the least causal information that any interleaving of source calls and $n$ verifications needs to succeed with probability $s$ is a list rate-distortion function, attained by one observation before any verification. It lower-bounds the expected number of binary source calls, which designed sources meet within $1+\log_25$ calls for unique answers and within a logarithmic term in general, where no additive constant suffices. With an exact verifier and fixed sources, moving every call before the first verification preserves all hard caps on calls, although interleaving can save unboundedly many expected calls; under a noisy verifier, source-first protocols can lose unbounded factors in information and in error. For linear banks over $\mathbb{F}_2$, optimal accuracy has a closed form, and after a
polynomial-time reduction the budget profile is computable in time $2^{O(h^2)}\operatorname{poly}(J,k+h)$ for $J$ sources and nuisance dimension $h$. In these banks, for zero error under a hard cap, the calls beyond the rounded-up information price are exactly those spent on nuisance. Every numbered result apart from two clauses about the planner is machine-checked in Lean 4, assuming two published results. Used as a ruler, the frontier shows a small
transformer using all delivered bits at latent dimension $5$ and none at $11$ within fixed training budgets; in a test with predictions recorded before training, low XOR degree of the target bits did not suffice for their use.
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Cryptography and Security
Poster: A Preliminary Study of LLM Distillation Inference
Edward Chen and Yuntao Du
Unauthorized model
distillation, in which a model is trained on the outputs of a proprietary large
language model (LLM), is a growing threat to model providers. We study
distillation inference: determining whether a suspect model was distilled from another model or trained independently. We formulate this problem as a hypothesis test and estimate the behavior expected under each hypothesis by training shadow models: distilled shadow models learn from the teacher's
reasoning traces, whereas independent shadow models learn only from reference answers. The auditor measures how closely each model predicts the teacher's
reasoning outputs and then uses the shadow models to convert the suspect's score into a calibrated p-value. In a preliminary study using Qwen2.5-7B as the teacher and Llama-3.2-3B for the suspects, our test achieves a true positive rate of 1.0 at a significance level of 0.02. These results demonstrate the feasibility of using
distillation inference to detect
distillation attacks.
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Cryptography and Security
Could LLM Watermark Detection be Public?
Georgios Milis, Tom Sander, Tomáš Souček et al. (+2 more)
Watermarking large
language models is popular for tracing chatbot and agentic outputs, yet detectors remain unreleased since exposing them could let attackers do targeted edits with the detector's feedback. However, watermarks are already vulnerable to uninformed tampering attacks. We thus first quantify whether a public detector would be an additional liability in a deployment setting at varying levels of access, from
token-level scores to a binary verdict. Second, we introduce a split-key public-private watermarking method that exposes one key through a public detector while keeping the other for full verification and forensics. An informed attacker can only move the public signal, creating an imbalance between public and private scores. We introduce a statistical test for this imbalance, and combine it with the full key verdict in a two-stage mechanism. Third, we evaluate the split-key method on a wide range of removal and forgery attacks, comparing the uninformed to detector-informed settings. Public detection improves removal only at small edit budgets, since plain rephrasing already strips the watermark at a lower quality cost, but it does enable forgery, which the private pipeline can identify. Overall, releasing half of the watermark enables transparency and interoperability, and tampering with the released half stays detectable. This bounds the provider's liability and questions the need to keep detectors fully private.
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All authors Georgios Milis, Tom Sander, Tomáš Souček, Heng Huang, Pierre Fernandez
Cryptography and Security
Protecting CPU AI On Edge TEEs: WebAssembly's Promise and Practical Challenges
Friedrich Vandenberghe, Lachlan Gunn, Bruno Volckaert et al. (+1 more)
AI models on edge hardware contain important intellectual property (IP), but an adversary can steal it when they achieve root access. Trusted Execution Environments (TEE) like Arm TrustZone protect against these Operating System (OS) level attacks. However, they are challenging to use. More precisely, it is difficult to run unaltered applications inside a TEE. This work presents a solution that allows the execution of unaltered AI models, compiled to WebAssembly, on the WebAssembly Micro Runtime (WAMR) in OP-TEE for Arm TrustZone. Additionally, this work provides an AI model distributor that encrypts the WebAssembly binary and places the encryption key in one of the device's fuses. This way, only the WAMR Trusted Application (TA) in OP-TEE can decrypt and execute the AI model. A thorough evaluation of our solution shows that it incurs an additional overhead of 22% in comparison to an application manually ported to OP-TEE, while also facilitating the execution of unaltered AI models with an additional inference latency of 6% without significant porting effort. Overall, there is a pressing need to safeguard the IP of AI models and this work shows that there is a real promise in WebAssembly, but there remain some practical challenges.
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All authors Friedrich Vandenberghe, Lachlan Gunn, Bruno Volckaert, Merlijn Sebrechts
Cryptography and Security
HPQ-AKE: A Provably Secure Sign-Less Hybrid Authenticated Key Exchange Protocol for Bandwidth-Constrained IoT and Edge Networks
Khiem Pham-Tuan, Minh Quang Le and Khuong Nguyen-An
Securing bandwidth-constrained Internet of Things (IoT) and edge networks during post-
quantum migration creates an authentication trade-off: ML-KEM provides post-
quantum key establishment, whereas post-
quantum signatures increase certificate-chain size, verification cost, and handshake latency. We present HPQ-AKE, a sign-less hybrid authenticated key exchange for RSA-enabled IoT gateways and edge/cloud services that replaces transcript signatures with dual KEMs. HPQ-AKE combines ML-KEM-768 for post-
quantum session secrecy and forward secrecy with RSA-OAEP for implicit mutual authentication, preserving existing RSA-enabled infrastructure during migration. We analyze HPQ-AKE in an extended Bellare-Rogaway model, separating classical authentication in the Random Oracle Model from session-key secrecy in the
Quantum Random Oracle Model. Under the Module-LWE and RSA assumptions, it establishes AKE security, forward secrecy, and conditional KCI resistance under the long-term-key-only exposure assumptions. Evaluation combines x86 micro-benchmarking, analytical latency modeling, and 10,000-iteration Monte Carlo simulation. HPQ-AKE reduces modeled handshake transmission from 13,009 to 5,668 Bytes, a 56.4% reduction relative to a Hybrid TLS 1.3 Full handshake, while requiring 7.11 ms of total local computation on the measured x86 testbed. Under a simulated 50 kbps satellite-like link with 600 ms RTT and
stochastic jitter, median latency is 1,914 ms, 31.4% below the 2,791 ms baseline. At 20 ms RTT, modeled break-even thresholds are 0.31 Mbps against the pre-cached baseline and 4.08 Mbps against the full baseline; both decrease as RTT increases. These x86-based results motivate evaluation on gateway-class IoT and edge platforms; performance on ARM gateways and unaccelerated microcontrollers remains unvalidated.
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Cryptography and Security
Moving Target Defense in SDN-enabled EV Charging Network
Roland Plaka, Mikael Asplund and Simin Nadjm-Tehran
Software-Defined Networking (SDN) is emerging as a promis- ing technology for EV Charging infrastructure (EVCI) since it enables flexible, programmable control of EVCI networks, yet its security gain to EVCI remains underexplored. SDN-enabled EVCI faces an increas- ing number of cyber threats arising from the convergence of IT and OT components; in particular, low-rate Denial-of-Service (DoS) attacks. Ear- lier works identify a trend toward low-rate attacks in OT networks that may exhaust SDN switch flow tables and which can result in disabling the entire charging sites without triggering volume-based defenses. In this paper, we propose CS-SHIELD, a Moving Target Defense mecha- nism for SDN-enabled EVCI communication. We showcase the imple- mentation of the proposed mechanism that detects malicious flow table rules via cross-layer identity verification and responds by reassigning virtual IP addresses to all active chargers. Experiments on an emulated SDN testbed with a real charging protocol implementation demonstrate that CS-SHIELD maintains full site availability under attack, responds quickly, adds only a negligible delay under normal conditions. The reas- signing (shuffle) approach at each reaction makes the earlier reconnais- sance knowledge by the attacker rendered worthless.
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Cryptography and Security
From Public Posts to AI-Search Citations: Measuring the Fragility of AI Search
Qi Liu, Geng Hong, Xinyang Zhang et al. (+3 more)
As more users ask AI systems for information, AI-search platforms are becoming a common gateway to web information. Unlike traditional search, which maps keywords to ranked pages, AI search retrieves pages, filters sources, selects citations, and generates answers before users see sources. This selection layer may amplify source bias and turn source choice into a security question. If a platform repeatedly cites domains where new users can publish posts easily, ordinary publication on those domains can become an indirect path into AI-search citations and answer text. Measuring this path is hard: platforms reveal little about citation selection, citations change over time, and the web contains so much background content that later answer changes are hard to attribute to our posts. We present a measurement framework for identifying and measuring this low-barrier publication path, combining cross-platform citation mapping, publication-barrier testing, and marker-controlled publication experiments. Across 10 AI-search platforms, we analyze 17,211 citation instances over 6,356 unique source domains and find: (1) citations concentrate in platform-specific sources, with top-20 domains capturing 20.5–70.8% of per-platform citations, and 15 of 22 tested publication platforms tied to cited source domains had low or medium barriers for both account setup and posting; (2) in our experiments, ordinary publication on preferred platforms changed what entered AI-search outputs: 8 of 10 platforms cited a fabricated concept within seven days, and one high-preference-platform article had greater citation impact than over 20 matched low-preference posts; and (3) this path is commercially available: a $14 GEO purchase produced 13 public posts, and one AI-search platform cited GEO-posted content with our designed markers within one hour.
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All authors Qi Liu, Geng Hong, Xinyang Zhang, Pei Chen, Yutong Li, Min Yang
Cryptography and Security
A Security Meta-Model for Retrieval-Augmented Generation Systems
Steve Nouyep, Sébastien Salva and Maxime Puys
Retrieval-Augmented Generation (RAG) systems extend large
language models (LLMs) with external knowledge through a multi-stage pipeline. While this architecture can improve the factual grounding of generated answers, it introduces structural attack surfaces that extend beyond those of standalone LLMs. In this paper, we introduce a security meta-model that captures explicit causal relationships between RAG surfaces, attacks, weaknesses, risks, and CIA impact (Confidentiality, Integrity, Availability). Its purpose is to provide security engineers with a structured and user-friendly framework for gathering and assessing the risks, weaknesses, and mitigations relevant to their RAG deployment. We designed the meta-model through an iterative, structured analysis of 43~publications (2023–2026) and instantiated it as a catalog populated with the security threats and remediations reported in the literature. Filtering the catalog according to a deployment configuration produces a risk profile containing the risks applicable to that deployment. An interactive web visualizer lets users navigate the catalog as a graph, follow causal chains, and explore stakeholder-specific views. Analysis of the catalog revealed a persistent imbalance between attack-focused and defense-focused research, a concentration of threats at ingestion, and coverage gaps affecting output integrity. Coverage is assessed against the OWASP LLM Top~10, and operational applicability is illustrated across textual, graph-based, and
multimodal RAG configurations.
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Cryptography and Security
Secure Aggregate Encryption with Identity-Based Authentication for Multi-Vendor FPGA Cloud Deployment
Mukta Debnath, Krishnendu Guha, Debasri Saha et al. (+2 more)
Secure deployment of FPGA bitstreams in heterogeneous multi-vendor cloud infrastructures requires scalable authorization, authenticated device access, and bitstream protection throughout the deployment lifecycle. Existing approaches typically address these functions through separate mechanisms, increasing coordination and key management requirements. This paper presents SAEID, a secure FPGA deployment framework that integrates aggregate authorization, certificate-free identity-based device authentication, and identity bound bitstream verification within a pairing based cryptographic framework, with symmetric cryptography used for session binding and AES 256 GCM based bitstream protection. Building on AgEID, an aggregate encryption scheme that enables individual decryption for authorized FPGA devices, SAEID extends the underlying framework to heterogeneous multi vendor deployments by supporting multiple FPGA vendors and IP providers, capability-aware authorization, and dynamic device membership. SAEID provides protection against unauthorized access to future deployments after device revocation and to prior deployments by newly enrolled devices, while retaining constant-size aggregate ciphertexts within each vendor domain and individual decryption. Experimental results demonstrate the practical performance of SAEID, with identity-based device authentication completing in approximately 4.35 ms and device membership updates requiring 4.95 to 5.09 micro seconds for device addition. The aggregate-encryption component exhibits scalable behavior with increasing device-set size. The complete SAEID software decryption path was also validated on a physical ZC702 Cortex A9 platform, requiring 191.126 ms. These results demonstrate scalable aggregate authorization with bounded authentication and dynamic-membership overhead for secure multi-vendor FPGA deployment.
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All authors Mukta Debnath, Krishnendu Guha, Debasri Saha, Amlan Chakrabarti, Susmita Sur-Kolay
Cryptography and Security · Cross-listed from cs.DS
Local Sensitivity in Exponential Selection: Failure Modes and Valid Calibrations
Dung Nguyen and Anil Vullikanti
Selection is a task that chooses one element from a finite public candidate range to maximize a data-dependent score. In differential
privacy (DP), the exponential mechanism (EM) samples a candidate at a temperature calibrated to the global sensitivity. In this paper, we study when
dataset-dependent sensitivity can safely replace global sensitivity in private selection. We propose three valid approaches. First, a private, high-probability upper bound on local sensitivity yields approximate DP, and the method extends to finite higher-order sensitivity hierarchies. Second, our Propose-Test-Release (PTR) variant privately searches a finite public grid for a temperature scale rather than fixing it in advance. Third, smooth sensitivity supports several designs. A candidate-independent smooth
geometric construction produces a sensitivity envelope that is admissible under the local dampening framework, which
privacy is guaranteed for any admissible envelope. Additionally, a separate logarithmic transformation utilizes smooth sensitivity to produce a smoothed candidate score function with advantages: having controlled global sensitivity, and preserving the maximizers of the original utility score, i.e., candidates maximizing the utility. Both of the designs yield range-independent pure DP. Besides that, we also give two approximate DP private selectors using smooth sensitivity: a direct EM with smooth sensitivity calibrated to the candidate range and
privacy parameters that matches a theoretical lower bound up to some constant factor, and one using a privatized smooth upper scale by analyzing the logarithmic transform of the smoothness. For every proposed mechanism, we derive a high-probability regret bound under its stated conditions.
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Cryptography and Security
SemField: A Simple, Linear, Continuous, yet Robust Semantic Watermark
Varun Gumma, Navonil Majumdar and Soujanya Poria
The rapid proliferation of Large
Language Models (LLMs) necessitates reliable watermarking techniques to identify AI-generated text and ensure appropriate attribution. While
token-based watermarks are vulnerable to paraphrasing, a central challenge for semantic watermarking is to turn sentence meanings into a stable, well-calibrated document-level signal. To this end, we introduce SemField, a simple, training-free semantic watermark that embeds a continuous, linear signal directly into the sentence
embedding space. Using a shared secret key to define a specific Gaussian direction, SemField iteratively evaluates candidate sentences and selects those that maximize the
alignment of the cumulative document aggregate with this targeted direction. We also propose SemField-PL, a polarity-locked variant that first determines the optimal orientation from the initial sentence and continuously reinforces it throughout the generation process. The document-level aggregated formulation guarantees exact invariance to sentence reordering and provides theoretical bounds against structural tampering, such as sentence insertion and deletion. Lastly, with extensive evaluations across three models, we demonstrate that both variants outperform 12 recent baselines. Across clean detection and four paraphrasing attacks, both variants achieve a mean True Positive Rate (TPR) of 88.2% to 90.4% at a 1% False Positive Rate (FPR), all while maintaining comparable perplexity and naturalness as human-generated content. We open-source our implementation at https://github.com/declare-lab/SemField
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Cryptography and Security
Anytime-valid detection of LLM weight exfiltration
Ines Ortega-Fernandez, Mateusz Kowalczyk and Keri Warr
A compromised LLM inference server can leak model weights by encoding payload bits in otherwise plausible
token choices. A replay of the same
prompt in a trusted server can expose such deviations, but benign numerical nondeterminism also causes
token mismatches. Patient attackers can therefore hide within normal variation unless evidence is combined across responses. We introduce a
prompt-level e-process that calibrates whole-response mismatch events on trusted benign traffic and accumulates evidence sequentially while, under a calibration-transfer assumption, controlling the probability of any false alarm over an unbounded monitoring horizon. We evaluate it on four models against a seed-blind attack and a stronger seed-aware attack that hides payload bits only in near-ties to remain stealthy, analyzing the channel capacity vs detectability trade-off. Compared with a hard per-
token alarm, the e-process combines weak evidence across responses while providing explicit anytime false-alarm control.
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Cryptography and Security
Host Attack Graph for Botnet Propagation
Andrei Neagu, Mara-Cristina Sterian and Paul Irofti
Botnets represent the backbone of most modern cybersecurity attacks through which botmasters deploy distributed denial of service and advanced persistent threats against legitimate computer networks. In this paper we introduce the Host Attack Graph model and propose two botnet propagation strategies which we study across network
topologies, target selection, and attack strategies together with their effectiveness in time. While strategy and botnet size are important for propagation, our study and simulations show that network
topology and target selection should not be easily discarded. Implementation and
benchmarks are available at https://codeberg.org/AndreiN/HAGP.
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Cryptography and Security
LTBD: Learnable Trust-Boundary Delimiters for Prompt Injection Defense
Luman Zhao, Minghui Xu, Yue Zhang et al. (+1 more)
Large
language models (LLMs) perform remarkably well on complex tasks, yet remain highly vulnerable to
prompt injection attacks, where malicious instructions embedded in external data can override user intent. Existing defenses remain limited by model fine-tuning requirements, vulnerability to adaptive attacks, or reliance on brittle handcrafted
prompts. We argue that a fundamental source of this vulnerability is the lack of an explicit representation of trust provenance. To address this, we introduce Learnable Trust-Boundary Delimiters (LTBD), a lightweight defense that explicitly encodes trust boundaries in the input while keeping the LLM parameters unchanged. LTBD uses a small number of learnable delimiters to distinguish trusted user instructions from untrusted external data, enabling the model to better respect the intended trust hierarchy. Experimental results show that LTBD substantially outperforms inference-time defenses and performs competitively with training-based approaches, while preserving benign-task utility and introducing negligible inference overhead. In particular, LTBD achieves 0.00% ASR on AlpacaFarm and only 0.11-0.19% ASR on TaskTracker. LTBD also remains effective under adaptive attacks, where adversaries have full knowledge of the defense and explicitly attempt to bypass it.
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All authors Luman Zhao, Minghui Xu, Yue Zhang, Yijun Yang
Cryptography and Security
Where Do the Tokens Go? Understanding and Reducing Costs in LLM Agents for Vulnerability Discovery
Li Lu, Yanjie Zhao, Hongjie Chen et al. (+1 more)
LLM
agents can spend millions of
tokens during vulnerability discovery without producing a working proof of concept (PoC). What consumes that budget, and why does it fail to produce results? We diagnose these costs and failures through a multi-axis open-coding study of 200 CyberGym traces, spanning four
agents (i.e., Codex, OpenCode, Cybench, and EnIGMA) under an unaided baseline and four existing efficiency methods. The study reveals three key findings. First, different
agents vary substantially in success and cost, and higher spending does not consistently yield better outcomes. Second, code localization and understanding, together with vulnerability
reasoning and trigger design, account for 60.4% of
tokens and represent the two leading bottlenecks in failed runs. Third, only 24.4% of matched comparisons preserve success at lower total cost; unsuitable signals and auxiliary overhead limit the benefits of existing methods. Motivated by these findings, we present AVRI, an
Agent-centric Vulnerability
Reasoning Interface built around a persistent Bidirectional Evidence Trace (BET). BET connects how the harness consumes input with the conditions required to make a selected operation unsafe, retaining source-supported correspondences alongside the
agent's hypotheses and open questions. Reading, analysis, and persistence commands help
agents build and reuse this evidence rather than repeatedly retrieve and reconstruct it. On 20 evaluation tasks, AVRI reduces total cost by 18.0% for Codex and 23.7% for OpenCode while preserving success rates and improving or maintaining recall.
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All authors Li Lu, Yanjie Zhao, Hongjie Chen, Haoyu Wang
Cryptography and Security
SoK: Are LLMs Reliable at Source Code Recovery? A Taxonomy and Empirical Evaluation
Varun Kohli, Lee Bing Cheng, Nur Hazim Ghazali et al. (+3 more)
Effective source recovery is critical to security applications such as malware analysis, vulnerability assessment, and legacy maintenance. Large
Language Models (LLMs) are reshaping this field, shifting the paradigm away from rule-based heuristics to probabilistic and high fidelity semantic recovery of source code from assembly or classical decompiler-derived pseudo-C. However, despite rapid progress, the field suffers from fragmentation across numerous approaches as well as their non-unified evaluations, limiting objective comparisons. Further, existing works have limited coverage of embedded, IoT architectures and source
languages beyond C/C++. In this work, we present the first Systematization of Knowledge (SoK) focused specifically on LLM-assisted binary-to-source recovery. We provide a granular design-centric taxonomy of LLM-assisted source recovery methods and systematic evaluations using seven key metrics along six evaluation dimensions. We evaluate state-of-the-art methods on 45,000 test samples derived from four standard and five embedded architectures, five optimization levels, and symbol stripping. We ablate the impact of design choices on recovery performance, including input representation, contextual enrichment, model scale, iteration and review roles using controlled in-house recovery pipelines and three off-the-shelf models. Finally, we test same-
language and cross-
language recovery capability covering four mature and two legacy
languages. Our systematization and comprehensive evaluations provide key insights that guide future directions in this field.
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All authors Varun Kohli, Lee Bing Cheng, Nur Hazim Ghazali, Gao Yuze, Daryl Poon, Dinil Mon Divakaran
Cryptography and Security
Certifying Hidden Paths: Scalable Topology Assurance for QKD Networks
Alessandro Colombo, Margherita Cozzolino, Stephan Krenn et al. (+1 more)
Large-scale
Quantum Key Distribution (QKD) networks rely on trusted repeaters, making the security properties of the selected communication path an essential part of end-to-end assurance. At the same time, network operators may be unwilling to disclose their internal
topology. We present a
topology-certification mechanism that lets a provider prove in zero knowledge that policy-compliant routes between two endpoints exist, without disclosing the routes in an individual presentation. Our main idea is to certify nodes and edges independently using multi-message signatures, rather than signing the complete graph as one object. For a route chosen in advance, proof size and cryptographic proving and verification work depend on its positions and attributes, independently of the overall network size, whereas route discovery and certification have separate graph-dependent costs. The construction hides the actual route length up to a public bound and sketches extensions to node-disjoint routes and monotonic additions within a graph epoch. We give a formal security model and conditional proofs of unforgeability and graph hiding for a generic construction. For a BBS-based construction, presentation-size estimates remain below $300$\,KiB at $\ell=m=n=50$, and measured generation and verification times remain below $400$\,ms at $\ell=64$ and $m=n=8$.
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All authors Alessandro Colombo, Margherita Cozzolino, Stephan Krenn, Thomas Lorünser
Cryptography and Security
EIFL: Efficiently Protecting Global Model Privacy and Integrity Against an Untrusted Server in Federated Learning
Zehui Liao, Qiang Li and Binghui Wang
Federated learning (FL) typically adopts a server-client architecture, where the server aggregates clients' local models (i.e., the input) and returns the aggregated global model (i.e., the output) to clients. An untrusted server may return a tampered global model to compromise the output integrity. Some existing schemes focus on verifying the output integrity. However, these schemes mostly rely on clients pre-negotiating a set of identical auxiliary information among themselves and keeping it confidential from the server. This dependency creates a verification vulnerability: if the auxiliary information is leaked, the verification method may be circumvented. Additionally, in some
privacy-sensitive scenarios (e.g., commercial
federated learning), the global model may need to be kept confidential from an untrusted server. However, only a few works achieve the output
privacy while addressing verification vulnerability, at the cost of prohibitive computation and communication overhead. To address these challenges simultaneously, we propose a novel provably
privacy-preserving FL method called EIFL. Specifically, we adopt a two-stage aggregation and combine it with symmetric encryption to protect the output
privacy. To address the verification vulnerability, we propose an efficient verification method based on vector inner product for output integrity, and a random vector generation method for clients to agree on auxiliary information. EIFL innovatively binds the auxiliary information to the output integrity, and eliminates the need to keep the auxiliary information confidential from the server. Moreover, EIFL is robust against client dropout during the verification phase through a simple resending operation. Evaluation results validate the advantages of EIFL over state-of-the-art schemes in terms of computation and communication overhead.
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Cryptography and Security · Cross-listed from cs.CV
Stop My Dancing! Understanding, Detecting and Attributing Motion-Aware Deepfake Videos
Fazhong Liu, Yan Meng, Tian Dong et al. (+2 more)
Pose-guided
diffusion models can now synthesize entire human figures in motion, spawning a new class of deepfakes: Motion Aware Deepfake (MAD) that have already reached hundreds of millions of viewers. To better understand this emerging threat, we construct the first MAD-specific
benchmark and measurement framework, containing over 1.5 million frames that mix 1,363 real and 30,122 synthetic
videos from six controllable generators, with realistic perturbations and open-world evaluation splits. Then, we dissect MAD and discover that, despite their global coherence, these
videos betray faint yet reliable cues: because the model relies on limited input frames for motion synthesis, it must predict and simulate coherent movement at motion boundaries, thereby producing high-frequency artifacts along with model-specific spectral fingerprints. Based on the observations obtained from analysis on
dataset, we propose MoDA, the first defense framework tailored to detect and attribute MAD
videos. MoDA couples spatial semantics with steganalysis-rich frequency features via cross-domain
alignment and multi-scale aggregation, achieving 94.8% in-distribution and 89.1% cross-
dataset detection accuracy gains of 10% to 25% over prior work and 91.5% model attribution accuracy. MoDA achieves 81.94% accuracy on 200 clips produced by two unseen commercial MAD platforms, indicating promising zero-shot transfer, and 78.13% detection accuracy on 1,200 unseen MAD
video clips (55k frames in total) collected from the open Internet. Under white-box, gray-box, and black-box adaptive attacks, MoDA maintains relatively stable detection and attribution performance while the accuracies of the baselines drop rapidly.
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All authors Fazhong Liu, Yan Meng, Tian Dong, Guoxing Chen, Haojin Zhu
Cryptography and Security
A Zero-Knowledge Signature Framework for Efficient Post-Quantum Message Authentication in Cooperative Automated Driving
Takahito Yoshizawa, Aysajan Abidin, Edoardo Pena-Gonzalez et al. (+1 more)
Connected and Automated Vehicles (CAV) rely on authenticated Vehicle-to-Everything (V2X) communications to exchange safety-critical information among vehicles and roadside infrastructure. As the automotive industry transitions toward post-
quantum cryptography (PQC), the significantly larger public keys and signatures of standardized PQC digital signature
algorithms introduce substantial communication overhead, which challenges the scalability of certificate-based V2X authentication, particularly for high-frequency cooperative awareness messages (CAM). This paper presents ZKS-PQC, a zero-knowledge signature framework that enables communication-efficient post-
quantum message authentication for cooperative V2X systems. Instead of transmitting complete post-
quantum public keys and signatures, the proposed framework replaces this authentication material with a compact Zero-Knowledge Proof (ZKP) while preserving compatibility with existing certificate-based trust architectures. This approach supports incremental migration and backward compatibility with the legacy ECDSA. The framework is implemented using the Open
Quantum Safe (liboqs) and ZKP (Bulletproofs) libraries, and we evaluated the performance of standardized NIST PQC signature
algorithms and additional candidate
algorithms. Experimental validation on both a Linux platform and a commercial On-Board Unit (OBU) demonstrates substantial reductions in message size exceeding 95% for all
algorithms, while limiting additional processing overhead by staying within the order of milliseconds at both sender and receiver in many
algorithms, consistent with the latency requirements of real-time V2X operation. By decoupling communication overhead from the size characteristics of post-
quantum signature
algorithms, ZKS-PQC offers a practical migration strategy for scalable,
quantum-resilient message authentication in future CAV systems.
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All authors Takahito Yoshizawa, Aysajan Abidin, Edoardo Pena-Gonzalez, Bart Preneel