Cryptography and Security · Cross-listed from cs.CY
Technology-Enhanced Tabletop Exercises for Cybersecurity Education: Lessons Learned
Jan Vykopal, Pavel Čeleda, Martin Horák et al. (+1 more)
This innovative practice full paper examines the integration of technology-enhanced tabletop exercises (TTXs) into computing education, focusing on cybersecurity curricula. The motivation is to better prepare students for complex, collaborative problem solving typical of incident response and IT governance, where coordination, communication, and timely decision-making are essential. Although TTXs are well-established in professional practice, they remain underused in universities. We address this gap by augmenting TTX delivery and evaluation through the INJECT Exercise Platform (IXP), a web-based environment that automates scenario flow and enables data-driven assessment. Our practice implements IXP to automatically deliver scenario updates, facilitate team discussions, and collect interaction data to support automated assessment. This combination enhances realism, reduces instructor workload, and provides actionable insight into student learning. From 2024 to 2026, we ran 25 exercises with 743 participants in multiple university courses and extracurricular events. We observed increased engagement and collaboration among students, and clearer visibility for instructors into how teams navigate complex scenarios. This paper shares 24 lessons learned from these exercises. Instructors and curriculum designers may benefit from concrete guidance for integrating technology-enhanced TTXs. We demonstrate that digital TTXs provide a scalable and replicable model for cybersecurity courses and others requiring team-based problem-solving.
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All authors Jan Vykopal, Pavel Čeleda, Martin Horák, Valdemar Švábenský
Cryptography and Security
Piggybacking on Perception: Stealthy Concurrent Audio Prompt Injections against Multimodal LLM Agents
Mingxiao Liu, Yitong Li, Haoren Zhao et al. (+6 more)
Large
Language Model (LLM)-driven
multimodal agents are increasingly deployed to execute autonomous tasks via continuous audio interaction. While this paradigm enhances interaction naturalness, it introduces a critical yet under-explored attack surface, as audio inputs inevitably contain environmental noise beyond user control. In this paper, we investigate concurrent audio
prompt injection attacks targeting
multimodal agents. Distinct from traditional acoustic attacks on voice devices, we propose novel techniques for instruction augmentation and scenario concealment. These methods allow malicious audio instructions to imperceptibly "piggyback" onto user
speech, thereby hijacking
agents to execute malicious actions. To systematically quantify this threat, we construct AudioAgentSecurity, the first comprehensive
benchmark for audio instruction injection attacks, encompassing 8 real-world task scenarios and 10 distinct attack patterns. We evaluate 11 state-of-the-art
agents, including Gemini 3 Pro and GPT-4o-audio. Notably, our methods achieve an average Attack Success Rate (ASR) of 69.10% against the advanced Gemini 3 Pro. To counter this threat, we further introduce Cascaded Audio Decoupling and Verification (CADV), a defense mechanism based on source separation and consistency analysis. Compared with existing
prompt-level defenses, CADV achieving up to 96% detection accuracy and providing effective protection against a broad range of acoustic injection attacks. Finally, real-world experiments with human volunteers on Doubao AI Smartphone in diverse dynamic real-world scenarios confirm the attacks' high stealth and efficacy, while demonstrating that our defense reliably mitigates these vulnerabilities.
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All authors Mingxiao Liu, Yitong Li, Haoren Zhao, Yaoxiang Bian, Jianan Ma, Jian Zhang, Jialuo Chen, Xinhao Deng, Zhen Wang
Cryptography and Security
Agent Harness Distillation: Inference-Time Harness Extraction and Exploitation in Autonomous Multi-Agent Systems
Yu Cui, Wuli Yang, Yirui Shi et al. (+4 more)
Autonomous multi-
agent systems (AMAS) built on large
language models (LLMs), such as Hermes, increasingly rely on inference-time harnesses to coordinate
reasoning and action. Constructing these harnesses requires substantial engineering effort and computational resources, as they are iteratively optimized over a combinatorial search space while co-evolving with the underlying LLM. Inference-time harnesses therefore constitute valuable intellectual property (IP). Although prior work has investigated IP leakage in static multi-
agent systems with pre-configured architectures, it remains unclear whether similar risks arise in AMAS, where harness behavior emerges dynamically during inference. To address this gap, we introduce
Agent Harness
Distillation (AHD), a framework for studying the security risks arising from inference-time harness extraction in AMAS. We formalize harness extraction as a new security problem and develop an evaluation framework for quantifying such risks. AHD extracts inference-time harness capabilities from a target
agent through black-box interactions and consists of two stages. In the pre-
distillation stage, AHD infers inference-time harness behaviors from the responses of the target
agent and constructs an initial harness. In the post-
distillation stage, AHD iteratively refines the initial harness to align with the behavioral patterns of the target
agent. Experiments on real-world AMAS across multiple backbone LLMs demonstrate the effectiveness of AHD and reveal substantial IP leakage risks. We further propose a deception-based defense that reduces harness extraction effectiveness while preserving the utility of the protected
agent. Our findings uncover a previously underexplored security threat to AMAS.
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All authors Yu Cui, Wuli Yang, Yirui Shi, Junhao Xia, Hui Jiang, Lei Gao, Chenfu Bao
Cryptography and Security
Checking Information Flow in Cloud-based IoT Access Control Policies (Extended Version)
Lorenzo Ceragioli, Letterio Galletta and Edoardo Lunati
Many cloud providers for IoT technologies offer access control mechanisms whose proper configuration is critical for security. However, verifying permissions in isolation is insufficient in a setting where devices have different levels of trust or are compartmentalised in various subsystems. This work analyses IoT access control policies to identify potential security vulnerabilities from unwanted information flow between devices. To this end, we formally model AWS IoT Core's components and define an information flow graph to capture the communication among devices permitted by the access control policies. We build a finite representation of the graph by leveraging an SMT solver, thus enabling the verification of information flow between devices. We implement our approach in a tool called IOT:POKER, and assess it on a realistic scenario and several real-world policies.
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Cryptography and Security
Temporal Poisoning: Clean-Label Backdoors via Event Redistribution in SNNs
Roberto Riaño, Gorka Abad, Stjepan Picek et al. (+1 more)
Backdoor attacks on Spiking Neural Networks (SNNs) have primarily assumed dirty-label poisoning, in which triggered training samples are relabeled to an attacker-selected class. We study clean-label temporal poisoning, where a fixed timestamp transformation is applied only to the target-class training streams, leaving their labels unchanged. The transformation preserves the per-pixel, per-polarity event count exactly, making clean and triggered samples identical after temporal aggregation while altering the sequence processed by the SNN. Across three neuromorphic
datasets and both convolutional and
transformer-based victims, the attack reaches an ASR of 1.00 in the strongest configurations. We analyze the attack through poison-budget and trigger-shape ablations and evaluate established backdoor defenses adapted to spiking models. Defenses that collapse the time axis before inspection are blind by construction, while feature-space methods detect the poison only in selected settings. Our model-free detector, based on per-step event mass, detects the evaluated temporal transformations, demonstrating both the limitation of rate-collapsed defenses and the boundary of the attack's stealth. To our knowledge, this is the first clean-label backdoor attack evaluated on SNNs and neuromorphic event data.
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All authors Roberto Riaño, Gorka Abad, Stjepan Picek, Aitor Urbieta
Cryptography and Security
Driving up Inference Energy on SNNs: Per-Sample and Universal Sponge Attacks
Spyridon Raptis and Haralampos-G. Stratigopoulos
Spiking Neural Networks (SNNs) communicate through sparse binary spike events rather than dense activations, enabling energy-efficient inference on neuromorphic hardware and motivating their use in always-on, battery-powered edge systems. We show that this same efficiency advantage creates a distinct security risk: sponge attacks can increase inference-time spike activity and synaptic workload, inflating energy consumption while remaining difficult to detect through correctness-based monitoring alone. Prior input-space efficiency attacks on SNNs have focused on per-sample optimization, primarily in rate-coded settings. We extend this threat to native event-based binary inputs and study two attack models. First, we develop a per-sample sponge attack that crafts a custom
adversarial spike train for each input via gradient-based optimization. This attack increases per-inference SynOps by 1.5-2.6x on three SNN models for the NMNIST, SHD, and IBM DVS Gesture
datasets, while preserving the predicted class on at least 98% of evaluated samples. Second, to the best of our knowledge, we introduce the first universal sponge attack for native event-based SNN inputs: a fixed binary perturbation computed offline and applied via XOR to all subsequent inputs. Although weaker, it still inflates SynOps by 1.09-1.24x across all three
datasets and represents a more realistic deployment threat because it requires no per-input optimization. Mapping SynOp inflation to estimated Loihi-1 energy yields per-inference overheads from 14 $\mu$J to 13.24 mJ. These results show that native event-based SNNs are vulnerable to practical input-space efficiency attacks, and that reusable universal perturbations can accumulate into meaningful battery drain in continuously deployed edge systems.
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Cryptography and Security
Safeguards Based on Copyable Context Cannot Provide Reliable Safety for LLMs
Pingyu Wu, Lingyao Zhu, Weiming Zhang et al. (+1 more)
Large
language model safeguards decide whether to answer before seeing how an answer will be used. This creates a basic problem for dual-use tasks: the same answer can help an authorized professional or an attacker, while an attacker can imitate a benign request and interaction history. We separate the capability released by the model from the evidence available about downstream use. When that evidence is copyable, we derive the exact worst-case floor on attacker assistance while preserving useful answers. The result yields a safety trilemma: Useful Capability, Reliable Safety, and Open Access cannot coexist. We then show how a trusted credential can complement existing safeguards by adding hard-to-copy information that predicts actual downstream use, and identify the stronger condition needed to eliminate the floor. Evidence from dual-use evaluations, adaptive attacks, and deployed trusted-access programs supports the practical relevance of these conditions.
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All authors Pingyu Wu, Lingyao Zhu, Weiming Zhang, Nenghai Yu
Cryptography and Security
Benign on Label, Malicious by Design: Clean-Label Dormant-to-Activated Backdoor via Machine Unlearning with Removable Camouflage
Dongdong Zhao, Can Li, Xiang Yao et al. (+3 more)
Existing backdoor attacks often become effective immediately after backdoor implantation and may therefore be exposed before exploitation. Machine unlearning activated dormant backdoors mitigate such behavioral exposure by remaining inactive after training and becoming effective only after selected training records are unlearned. However, existing methods struggle to simultaneously achieve a low pre-unlearning attack success rate and strong post-unlearning activation under clean-label constraints and realistic unlearning requests. Achieving this transition requires jointly establishing a persistent latent association and a removable suppressive influence. To address this challenge, we propose a clean-label unlearning-activated backdoor framework based on dual-generator learning and formulate it as a bilevel optimization problem: By simulating latent backdoor establishment and machine unlearning, the framework alternately learns sample-specific triggers that establish a latent trigger-to-target association and label-consistent camouflage samples that provide removable suppression. Once a small subset of camouflage samples is unlearned, the suppression is lifted and the dormant backdoor is activated. Experiments on CIFAR-10 and ImageNet-10 show that our method maintains lower pre-unlearning attack success rates while achieving stronger post-unlearning activation across multiple unlearning
algorithms than representative backdoor baselines. These results demonstrate that reliable dormancy-to-activation transitions can be achieved by coordinating a persistent latent association with removable suppression under clean-label and realistic deletion constraints.
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All authors Dongdong Zhao, Can Li, Xiang Yao, Fan He, Qihang Ge, Baogang Song
Cryptography and Security
Don't Trust the AI Ecosystem: Analyzing Privacy Leakage in Compromised Open-Source Components
Jin-Seong Kim, Han-Ju Lee, Seok-Won Hong et al. (+4 more)
Existing model inversion (MI) attacks predominantly rely on post-training optimization to recover private data from model outputs. However, these methods are fundamentally constrained by the target model's generalization bottleneck, often yielding generic features rather than specific identities, particularly on high-dimensional
datasets. In this paper, we introduce GradLock, a novel training-time injection attack that stealthily injects sensitive training data directly into the model parameters. Operating within a compromised supply chain context, GradLock leverages stateless deterministic indexing to establish isolated data vaults and employs dynamic gradient locking to prevent payload degradation during the optimization process. This mechanism allows the adversary to extract pixel-perfect data from the final model without retaining access to the training environment. Extensive experiments on MNIST, Imagenette, and CelebA demonstrate that GradLock achieves near-lossless reconstruction (SSIM ~ 1.0) and instant extraction (< 1.0s). Compared to existing training-time injection methods, our approach exhibits superior robustness against standard deployment optimizations, including quantization,
pruning, and fine-tuning. Furthermore, a user deployment study reveals that 93.3% of participants failed to detect the malicious logic, highlighting a severe blind spot in the security of modern AI supply chains.
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All authors Jin-Seong Kim, Han-Ju Lee, Seok-Won Hong, Takeshi Takahashi, Chansu Han, Tomohiro Morikawa, Seok-Hwan Choi
Cryptography and Security
Adaptive Security at the Edge for 6G-Enabled Healthcare IoT
Ijaz Ahmad, Ijaz Ahmad and Erkki Harjula
Healthcare IoT services increasingly rely on edge gateways to relay routine telemetry and deliver rare but timecritical alarms. Even short traffic bursts can inflate worstcase delay and interfere with urgent messages. We present NANOEDGEGUARD, a kernel-plane closed-loop controller that observes per-source traffic intensity at the edge and enforces an auditable, multi-tier rate policy using in-kernel traffic-control hooks. Unlike static firewall rules or user-space control loops, our design prioritizes fast actuation and explicit recovery through hysteresis, and it records policy transitions for auditability. Using a Raspberry Pi gateway hosting an MQTT broker and two ESP32 endpoints generating vitals, alarms, and a timed burst, we show that adaptive kernel-plane rate control reduces the 99th-percentile alarm RTT by 13.3% compared to a user-space firewall baseline while maintaining no-enforcement-level RTT, and it reduces excess admitted burst traffic by 46% compared to no enforcement. These early results indicate that adaptive, auditable enforcement at the gateway can improve resilience for healthcare IoT, and it can be extended toward on-demand policy deployment in future edge intelligence.
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Cryptography and Security
CHARGE: Leveraging CWE Hierarchies for Hardware Security SystemVerilog Assertion Generation
Xiao Tan and Cynthia Sturton
This paper presents CHARGE, an automated framework for generating security properties for unverified RTL modules using CWEs and large
language models (LLMs). The hallmark is a
reasoning process that leverages the hierarchical nature of CWE entries to improve accuracy when identifying security-critical assets in unverified RTL modules. As a result, the approach can infer expected security behaviors and generate properties from identified assets and CWE semantics, avoiding the need for trusted design specifications and reducing manual engineering effort. We evaluate the framework on the Hack@DAC18, 19, and 21 open source SoC designs using OpenAI's GPT-4.1. CHARGE detects 27 of 42 known bugs in these designs. For Hack@DAC21 OpenPiton SoC, 89% of the generated SVAs run in Cadence JasperGold FPV, and 92.2% are non-vacuous. We compare to an open-source, manually written set of properties for these designs and find that CHARGE correctly writes properties for three bugs in which the manually written properties were incorrect. In addition, CHARGE-generated properties identify a new bug in the Hack@DAC21 OpenPiton SoC that was not previously identified.
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Cryptography and Security
Distributed Point Functions and Function Secret Sharing
Elette Boyle, Niv Gilboa, Yuval Ishai et al. (+1 more)
A distributed point function (DPF) is a cryptographic primitive that enables compressed additive sharing of a secret weight-1 vector (equivalently, a point function) across two or more parties. The appealing lightweight structure of DPF constructions has enabled a wide range of applications. These include private information
retrieval, anonymous messaging, secure computation with preprocessing, and pseudorandom correlation generators for expanding small correlated seeds into large pseudorandom instances of cryptographic correlations. In this article, we survey definitions, constructions, and applications of DPFs. We also discuss the extension of DPF to function secret sharing (FSS), which generalizes point functions to support richer function classes. Efficient FSS schemes yield a similar generalization for most of the applications of DPFs.
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All authors Elette Boyle, Niv Gilboa, Yuval Ishai, Peter Scholl
Cryptography and Security
Strategy Phasing of Cyber Attacks on Digital Substations
Akila Herath, Chen-Ching Liu, Junho Hong et al. (+1 more)
Digital substations that comply with IEC 61850 have improved the operational efficiency of modern power systems. However, adversaries can abuse IEC 61850 communication to manipulate
circuit breaker operations in substations, which can result in severe system impacts. These cyber attacks are crafted based on broader multi-phase strategies. The existing intrusion detection systems (IDSs) often flag only isolated symptoms. Thus, there is a lack of context in the attack phase to support the deployment of mitigation measures. This paper proposes Substation Cyber Attack Strategy Phasing (SubCASP), a Hidden Markov Model(HMM)- based method that fuses IDS data logs to infer the current attack phase, next attack phase, and retrospective attack path. The attack phases are derived from an ATT&CK-based threat modeling. The SubCASP model is trained and evaluated on a reproducible attack-graph
dataset. Test results are presented to demonstrate the robustness of SubCASP for various IDS observability levels and missing IDS data logs scenarios.
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All authors Akila Herath, Chen-Ching Liu, Junho Hong, Kuchan Park
Cryptography and Security
Revisiting the Adversarial Robustness of Graph-Based Traffic Forecasting
Qingzhao Zhang
Traffic forecasting by graph-based AI is a critical component of intelligent transportation systems, motivating security research on robustness to malicious sensor readings. We argue that prior robustness evaluations are largely shaped by unrealistic threat models and untargeted objectives, so both attacks and defenses must be revisited. We study a practical adversary with limited model knowledge and the ability to monitor and manipulate only a few road sensors. More importantly, practical attacks can be localized to specific links or routes, causing incorrect estimated arrival times or unnecessary rerouting while leaving the broader network largely unaffected. This targeted setting remains underexplored, and defenses such as
adversarial training do not transfer well from the norm-bounded attacks they train on to structurally different, physics-aware attacks that mimic genuine congestion. We therefore reframe robustness as a detection problem, introducing a learned physics-informed detector whose output is fed to a hardened forecaster as an input feature and trained against adaptive attacks with the forecaster fixed. We evaluate across a variety of model architectures and
benchmarks. The physics-aware attack multiplies target-link error several-fold while the network-wide error barely moves, and
adversarial training, tuned to norm-bounded perturbations, barely dents it. Our detection–mitigation defense improves even on
adversarial training hardened against the physics-aware attack itself, on $13$ of $15$ model–
dataset settings and by the widest margin on a held-out attack, at near-zero clean cost. The results emphasize the need to examine abstracted AI
adversarial attacks under application-specific constraints to assess their true security impacts.
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Cryptography and Security
AnchorMark: Robust Diffusion Watermarking via Latent-Space Rotation Synchrony
Yuqi Qian, Yun Cao, Haocheng Fu et al. (+3 more)
Inversion-based watermarking embeds watermark payloads directly into the generative process, avoiding a separate post-hoc image-domain
embedding stage while preserving the native visual fidelity of synthesized images. However, existing methods remain vulnerable to compound lossy post-processing, particularly when rotation is involved, as it disrupts the spatial correspondence required for latent-space decoding. To overcome this limitation, we introduce AnchorMark, a training-free, robust inversion-based watermarking. We uncover a latent-space property termed Rotation Synchrony: image-domain rotations and their counterparts in the recovered initial latent share the same angle. Building on this property, AnchorMark embeds a synchronization anchor in the central region of the initial latent, enabling accurate estimation and correction of the rotation angle during extraction. Experiments show that AnchorMark substantially improves bit accuracy under rotation and combined attacks, with limited impact on image quality.
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All authors Yuqi Qian, Yun Cao, Haocheng Fu, Haochen Zhao, Hong Zhang, Meineng Zhu