Cryptography and Security · Cross-listed from cs.NI
Comparing UPF Dataplane I/O Modes in a Cloud-Native 5G Core: AF_PACKET, AF_XDP, CNDP, and DPDK on SD-Core BESS-UPF
Shiva Valia, Nitin Rajput, Aditya Gairola et al. (+1 more)
The User Plane Function (UPF) carries all user-plane traffic in a 5G network, and its throughput depends on how packets move between the NIC and the application, that is, on the packet I/O mode. We compare four widely used modes, AF_PACKET, AF_XDP, the Cloud Native Data Plane (CNDP), and the Data Plane Development Kit (DPDK), on a single open-source UPF. Using SD-Core BESS-UPF deployed as a Charmed operator on Intel XXV710 NICs in Canonical Kubernetes, we run the same GTP-U/PDR/FAR/QER pipeline under each mode and change only the BESS port driver, so any difference is attributable to the I/O backend. For each mode we describe its architecture, datapath,
memory model, and deployment requirements, and we measure throughput, latency, CPU usage, and stability; the deployment is also validated end-to-end against a disaggregated O-RAN 5G RAN with a commercial UE. On an XXV710/i40e testbed (NDR per RFC 2544) at 64 B, AF_PACKET reaches 0.25 Mpps, CNDP 5.52 and AF_XDP 6.47 Mpps at 2 workers, and DPDK 10.30 Mpps at 4 workers and 13.09 at 8, with the lowest latency (8.1 microseconds average). At matched worker counts the three kernel-bypass modes are within noise and AF_XDP leads per core; DPDK's advantage is a scaling-ceiling effect, since its native PMD over vfio-pci escapes the per-netdev AF_XDP socket limit that pins CNDP and AF_XDP at two workers, not a per-packet efficiency win. CNDP and AF_XDP are the cloud-native sweet spot when hugepages, vfio-pci, and isolated cores are unaffordable; DPDK is justified on dedicated hosts. We also document deployment pitfalls absent from synthetic
benchmarks, including a Kubernetes limits.cpu mis-setting that silently halved DPDK throughput. The paper is a side-by-side reference for operators choosing a UPF dataplane mode in a cloud-native 5G deployment.
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All authors Shiva Valia, Nitin Rajput, Aditya Gairola, Vipin Rathi
Cryptography and Security
How Stable Is a PNT Resilience Score? Decision-Instability of Single-Number Resilience Ratings under Framework-Aligned Weighting
Chakshu Baweja
Authoritative positioning,
navigation, and timing (PNT) resilience frameworks (the DHS Resilient PNT Conformance Framework, RPCF, and peers) define what resilience means but supply only self-attestation: a checklist or a maturity Level, with no engine and no measurement. We build the missing measurement layer as an open, deterministic scoring engine over a PNT simulator, emitting per-dimension sub-scores traceable to a scenario and an oracle, and ask whether a single composite score or maturity Level is a stable basis for a decision. Across seven architectures spanning cross-dimension tradeoffs, a Dirichlet simplex over the seven RPCF categories, and a five-threat ensemble, the answer splits in two. The composite winner is stable under active denial and under near-equal weightings (about 1 percent flip rate), so a single number is safe precisely where one design dominates; but re-weighting alone flips it in up to 22 percent of draws under nominal conditions, where designs contend, a known composite-indicator sensitivity. The sharper, weighting-invariant failure is categorical: a weakest-link maturity Level (our minimum-over-categories operationalization of the RPCF ladder, not the framework's rule) depends on the threat assumed, not the architecture, changing for one architecture in seven. Because the composite rewards declared techniques, a constructed single-band receiver declaring all seven outscores a more resilient system: self-attestation can be gamed by declaration. And apparent fourfold GNSS redundancy reduces, by the definition of a shared common-mode failure domain, to an effective diversity of one. Conclusions hold under +/-20 percent perturbation of every driver within the reduction. We report per-dimension sub-scores with provenance and a rank range, not a phantom single number. A self-assessment aligned to RPCF v2.0, not a certification.
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Cryptography and Security
Quantum-Resilient Decentralized AI Economies: Proof-of-Useful-Work and Post-Quantum Security
Connor Barbaccia, Sudip Vhaduri and Sayanton Dibbo
Proof-of-Work blockchains secure consensus through hash puzzles, producing no external value. In this research, we propose a decentralized AI economy where nodes are rewarded for useful machine-learning work, i.e., inference and training, instead of ineffective hashing method. Our proposed three-layer architecture separates compute, validation, and economic coordination. We formalize it via a $(\theta_c, \theta_w, W)$-closed-loop
token economy and derive a sufficient-stake condition for honest participation. While existing Grover's
algorithm provides only a quadratic speedup against hash puzzles, it does not accelerate ML-native linear
algebra. On the other hand, Shor's
algorithm threatens classical blockchain signatures. Post-
quantum migration to
lattice-based and hash-based standards can address the signature layer. Therefore, useful-work consensus thus offers both economic and
quantum-security advantages over classical proof-of-work.
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Cryptography and Security
Unprivileged Topology Certificates for Cloud GPU Attestation
Faruk Alpay and Taylan Alpay
Cloud GPU tenants receive a model name and a region, but cannot directly inspect the physical accelerator that runs their job. We present a software-only attestation primitive for this setting. A CUDA probe measures an SM-by-
memory-region latency
matrix using physical SM labels and dependent global loads. A streaming reducer commits sufficient statistics, configuration, code hashes, network evidence, and a compressed raw data archive into a certificate that a verifier can check without a GPU. The certificate supports three claims. First, the per-SM latency map is a stable physical fingerprint. Over a six-hour full-load RTX 5090 run, its median temporal jitter is 0.09 cycles, while shape-only leave-one-out classification separates distinct Blackwell dies with 100.0% accuracy. Second, cache-bypassing HBM sweeps recover hardware-class
topology across generations, including a unified Volta V100
memory domain, a two-way Hopper H200 L2 split, and a Blackwell B200 two-die NV-HBI package whose 74/74 SM partition carries a 30-cycle, 15.5 ns cross-die penalty. Third, public network landmarks bind the same certificate to a coarse location. In the B200 run, 169 RIPE Atlas probes place the server within 44 km of its claimed datacentre and reject all 11 decoy sites. Together, these measurements check cloud-GPU identity, class, and coarse location without privileged access or a vendor key.
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Cryptography and Security · Cross-listed from cs.LG
Cyclic Denoising Reveals Ultrastable Memories in Diffusion Models
Rishabh Sharma and Stefano Martiniani
We introduce cyclic denoising – repeated forward and reverse
diffusion at controlled noise amplitudes – as an extraction attack for image
diffusion models. Inspired by random organization in disordered solids, cyclic denoising exposes regions of the learned distribution that are largely inaccessible to standard sampling. The dynamics drive samples toward attractors with a broad stability spectrum. The deepest attractors are ultrastable: they regenerate after near-total corruption and persist through thousands of noising-denoising cycles. Many of these attractors correspond to memorized training images, including stock photographs, brand watermarks, and web-crawl artifacts. The attack requires only sampler-level control, with no gradients, weight inspection,
prompts, captions, or prior knowledge of the training data. Unlike generate-and-filter attacks, which rely on large-scale prompted generation and post-hoc similarity or membership-inference filtering, our main protocol is fully unconditioned. We demonstrate the phenomenon in Stable
Diffusion v1.4 and in a pixel-space DDPM, showing consistent behavior across latent- and pixel-space
diffusion models. Across noise amplitudes, we observe a yielding-like transition: low-amplitude cycling produces trivial absorbing fixed points or limit cycles, while larger amplitudes induce rearrangements, basin hopping, and long-lived trapping in structured memorized attractor basins. We also observe hierarchical partial absorption,
prompt-stabilized basins, and cross-initial-condition universality of the recovered attractor set. Our results therefore show that cyclic denoising is both a physics-inspired probe of generative landscapes and a practical tool for memorization
auditing, with implications for
privacy, copyright compliance, and model fingerprinting.
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Cryptography and Security
Maestro Order: A Model-Agnostic Orchestration Harness
Hidayet Aksu
A single forward pass of a capable model is a fast, fluent, and unreliable problem-solver: it is right often enough to be useful and wrong often enough to be dangerous; in
language models, such confident errors are known as
hallucinations. We present Maestro Order, a model-agnostic orchestration harness that turns unreliable solvers into reliable problem-solving systems by composing them according to four structural primitives (decompose, ensemble, verify, and recurse) and a budget-aware controller that decides where to spend compute. The harness treats any model as a black-box base solver behind a uniform interface, layers a verifier ensemble whose discrimination is measured online, and allocates verification and voting to the stages with the highest marginal reliability per unit cost. We give the architecture, the message and state schema, the controller
algorithm, and the engineering that makes it deterministic, observable, and fault-tolerant. We then specify an evaluation methodology (reliability at fixed cost, coverage, calibration, and ablations) and report results from a faithful Monte Carlo simulation of the harness over a parameterized solver/verifier model. The simulation reproduces the predicted laws quantitatively: verification amplifies reliability geometrically (e.g. $0.55\to0.98$ with two gates, $\to0.999$ with four), voting helps only above chance and is limited by shared errors, and a budget-aware controller reaches a target reliability at a small fraction of the cost of voting alone by selecting the cheapest mechanism for each regime. We close with failure modes (verifier gaming, correlated errors, and decomposition error compounding) and concrete guidance: build robust checkers, diversify solvers, and let the controller put compute where the information is.
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Cryptography and Security · Cross-listed from cs.DC
The Serialized Bridge: Understanding and Recovering LLM Serving Performance under Blackwell GPU Confidential Computing
Hang Yin and Kevin Wang
GPU Confidential Computing (GPU-CC) now preserves GPU-local performance: on NVIDIA B300, BF16 matmul runs at 0.998x of non-confidential performance. Yet LLM serving under Intel TDX plus GPU-CC still loses 13-27% of throughput, and KV-cache restore latency can more than double. This paper studies that gap on two Blackwell platforms, RTX Pro 6000 and B300 HGX, and identifies its dominant cause: the confidential VM-GPU bridge, not GPU compute. We find that GPU-CC turns host/device movement into a serialized, high-setup-cost channel. Secure copies do not gain CUDA-stream concurrency within a context, asynchronous transfers block at the runtime boundary, and small crossings pay a fixed toll. This violates the assumptions of modern inference runtimes, where DMA is expected to be cheap, concurrent, and asynchronous. In vLLM dense decode, the gap closes around 44x-slower small alloc-and-copy operations; targeted patches reject alternative explanations. A scheduling flag recovers 57% of the gap, while a worker-thread drain recovers up to 92% in qualified high-concurrency runs. The same bridge model explains a +131% KV-restore penalty and a 34x model-load slowdown. Blackwell also changes the confidential tenancy unit. We qualify confidential multi-GPU NVSwitch tenants on B300, including 510 GB/s NVLink P2P inside a CVM and concurrent isolated tenants, and identify the remaining fabric-attestation gap for production confidential AI platforms.
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Cryptography and Security
BipBipCache: Pipeline-Aware Integration of Low-Latency Tweakable Encryption in an Embedded Cache Controller
Corbin Hibler, Firas Hassan and Eric McKanna
Consumer and embedded processors store sensitive data in on-chip SRAM caches that remain readable after power loss or physical probing unless ciphertext is maintained in the
memory array itself. This paper presents BipBipCache, a direct-mapped cache controller that integrates the BipBip tweakable block cipher (TBC) to encrypt cache data and tags in real time using a C$^3$-style 24+40 bit decomposition of each 64-bit word. We reconstruct the first pipelined hardware BipBip encryptor from a decryptor-centric specification and coordinate it with a 3-cycle decryptor inside the cache datapath. Our threat model targets confidentiality of cache-resident contents against cold-boot, bus, and SRAM readout attacks. A key architectural result is that 6-cycle encryption latency does not fully translate into 6-cycle write penalty: the first three encryptor stages overlap with tag decryption and hit detection, leaving an effective 3-cycle write commitment after hit verification. We verify encryptor and decryptor correctness against the official BipBip C++ reference (five vectors each), report FPGA resource utilization on Xilinx Artix-7 (3,356 LUTs, 16.1% of device; crypto logic ~79% of LUTs), and confirm end-to-end operation on hardware.
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Cryptography and Security
AutoPRAC: Automating Attack Discovery for PRAC-Based Rowhammer Defenses using Model Checkers
Joyce Qu and Gururaj Saileshwar
Per-Row Activation Counting (PRAC) in DDR5 is a specification to mitigate Rowhammer attacks by tracking activations per row and triggering mitigative refreshes when needed. However, the security of PRAC designs is currently evaluated using human-crafted attack patterns and we lack formal verification of their security properties, or automated techniques to detect implementation flaws. In this work, we present AutoPRAC, the first automated technique to test the security of PRAC-based defenses using model checkers. AutoPRAC models PRAC implementations as bounded state machines and checks security-critical safety properties against a worst-case oracle attacker. If a property is violated, the framework produces a concrete counterexample trace corresponding to a successful attack. Using AutoPRAC, we uncover a previously unreported flaw in MOAT, a state-of-the-art PRAC defense, in its counter-reset policy that allows up to 34 activations to go undetected above the Rowhammer threshold. Our results demonstrate that AutoPRAC can automatically discover subtle security flaws in Rowhammer mitigations and serves as an early-stage design aid for attack discovery on PRAC designs.
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Cryptography and Security · Cross-listed from cs.LG
Are Safety Guarantees in Neural Networks Safe? How to Compute Trustworthy Robustness Certifications
Merkouris Papamichail, Konstantinos Varsos, Giorgos Flouris et al. (+1 more)
A primary challenge in AI safety is the existence of
adversarial examples – slightly distorted inputs that cause a neural network (NN) to misclassify. To mitigate this problem, recent research focuses on the computation of robustness certifications, which, for a given input, determine the largest distortion the input may receive without breaking the network's prediction. Robustness certifications can be interpreted as an axis-aligned hyper-rectangle (multi-dimensional intervals). Most existing approaches focus on maximizing the certification's volume, but recent intractability results prohibit the computation of volume-optimal certifications in reasonable time. We introduce the apothem measure and show how to compute apothem-optimal certifications in a linear number of calls to a NN verifier (oracle) w.r.t. the input domain's diameter. Moreover, we prove that we cannot have a volume-optimal, oracle-based
algorithm, even if we discard the oracle costs. Also, we introduce dual certifications – an interval including all instances of a class – thus providing apothem-minimum upper bounds to a robustness certification. Further, we present the ParallelepipedoNN system, which we evaluate on the standard MNIST and Fashion MNIST
benchmarks. A preliminary comparison with existing work on the same
datasets reveals at least two-fold improvement w.r.t. the minimum edge length.
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All authors Merkouris Papamichail, Konstantinos Varsos, Giorgos Flouris, João Marques-Silva
Cryptography and Security
Cryptographic certificates of validity for trustworthy AI
Murdoch J. Gabbay
We propose cryptographic certificates of validity for agentic AI systems. The core idea is to formally specify a correctness or policy condition as a logical predicate, compile this predicate to a witness-checking problem over
polynomial constraints, and use a succinct cryptographic proof system (and optionally zero-knowledge) to certify that the condition holds. This offers a middle ground between formal verification of source code, and cryptographic authentication. An
agent's action can be accompanied by an independently checkable proof that it satisfies an agreed formal policy, without requiring the verifier to trust the
agent or to re-execute computation. We outline the approach at a high level, give the core mathematical translation, relate the proposal to proof-carrying code, zkVMs, formal methods, and
agent governance, and note the specification,
auditing, and deployment questions that a full implementation must answer.
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Cryptography and Security · Cross-listed from quant-ph
Gopikrishnan Muraleedharan, Minh Thuy Truc Pham, Vir Pathak et al. (+10 more)
We provide a pre-obfuscation
circuit-level implementation of an efficient one shot signature scheme, which has known applications to delegated signatures, secure
token transfer, and publicly verifiable randomness. The
algorithm consists of two stages: a key generation stage where a classical public key/
quantum secret key pair is produced, and a signing stage where the
quantum secret key is processed with a message string to produce a classical signature. There is no algorithmic error in the construction and the signed message can be efficiently checked by a classical verifier. Our scheme works by preparing a superposition over elements of a random affine coset determined by the output of a puncturable pseudorandom function, together with a
circuit that tests coset membership. The logical
qubit number scales like $\Theta( \kappa\log(r) + n + l)$ and the gate complexity scales like $\Theta(n^3 + nl)$, where $r$ is the public key size, $n+l$ is the signature size, $l$ is the message size, and $\kappa = \Omega(n)$ is the cryptographic security parameter. We provide explicit
qubit and gate counts before obfuscation. A secure instantiation additionally requires modified key generation and a security proof for the resulting obfuscated construction.
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All authors Gopikrishnan Muraleedharan, Minh Thuy Truc Pham, Vir Pathak, Thomas Gardner, Chuanqi Zhang, Samuel Crew, Tom Hartweg, Adrian Aasen, Guido Masella, Vase Moeini, Asier Piñeiro Orioli, Hugo Perrin, Gavin K. Brennen
Cryptography and Security · Cross-listed from math.CO
Optimal Small Set Expanders and Their Codes
Tristram Bogart, Marcelo Fiori, Pedro Raigorodsky et al. (+1 more)
A left-regular bipartite graph $G$ of degree $d$ is called a $(t,\alpha)$-small-set-expander if every subset $X$ of left vertices of size at most $t$ has at least $\alpha |X|$ neighbors. Such a graph is an optimal small-set expander if small subsets have as many neighbors as possible. We characterize optimal expanders combinatorially via girth and prove the existence of $s$-optimal expanders for every $s$. We also prove that $s$-optimality yields new "transfer" lower bounds on the number of neighbors of sets of size $h\geq s$. Finally, as an application, we discuss the use of optimal small-set expanders in building good codes for key exchange protocols in post-
quantum cryptography.
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All authors Tristram Bogart, Marcelo Fiori, Pedro Raigorodsky, Mauricio Velasco
Cryptography and Security
A Watermark for Vision-Language-Action and World Action Models
Yule Liu, Shuai Liu, Jiaheng Wei et al. (+1 more)
Vision-
language-action (VLA) models and world-action models (WAM) are the generative models now driving general-purpose
robot control, turning raw camera input directly into motor commands. They are increasingly deployed as black-box services, where a partner runs the policy through an interface while the owner keeps the weights private. Training such a model takes proprietary data and heavy computational power, making the deployed model itself a valuable intellectual property. To address this, we propose the keyed latent-provenance verification method, which fingerprints the policy through the seed of the Gaussian noise vector that the models draw before generation. At the injection stage, the owner swaps this seed for a keyed one with the same distribution as ordinary noise, so the fingerprinted actions are statistically identical to those of an ordinary run and an adversary watching the output finds no signal to detect or remove. At the verification stage, the owner runs the suspect model under authorized access and records the action channels the
robot executes, a partial and possibly post-processed view of the policy's output. From this view, the verifier recovers the seed by gradient-based maximum a posteriori (MAP) optimization, tests it for the secret key to score each rollout, and aggregates these scores into a single decision on whether the suspect model belongs to the owner. We evaluate the method on two representative models across two
robot suites. The experiments cover detection of the fingerprint, identification of which of several keys a suspect carries, robustness to a range of attacks, and an analysis of why the design works. Across both models, the fingerprint can be detected reliably with little change to task performance, and it remains detectable under output-side removal attacks and weight-level edits.
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All authors Yule Liu, Shuai Liu, Jiaheng Wei, Xinlei He
Cryptography and Security · Cross-listed from cs.LG
TROPT: An Open Framework for Unifying and Advancing Discrete Text Optimization
Matan Ben-Tov and Mahmood Sharif
Discrete text-trigger optimization – searching for text sequences that, when ingested by a model, steer it toward a specified objective – underpins model red-teaming (e.g., LLM jailbreaks), as well as
auditing and interpretability. However, the current state of discrete optimizers hinders their adoption and progress. First, existing optimizers, when open-sourced at all, are scattered across research codebases tied to specific models, objectives, and problem domains. Second, optimizer variants proliferate, each requiring engineering overhead to use or extend, and remaining hard to compare head-to-head. Together, these raise the bar for adopting optimizers in existing or new domains, and for advancing them via new strategies. We address these gaps with TROPT, the first open-source framework that unifies discrete optimizers' execution and standardizes their development under a single interface. TROPT makes it easy to customize end-to-end optimization recipes by swapping any component – models, objectives, and optimizers – extending its reach across domains and new applications. TROPT currently ships with 30+ optimization recipes – covering applications such as jailbreaking and probing model internals – built from 15+ optimizers (spanning white-box to black-box access) and 15+ losses, from foundational to state-of-the-art methods. Demonstrating its utility, we leverage TROPT in several studies: (i) controlled, large-scale experiments comparing and enhancing optimization strategies for LLM jailbreaks, revealing potent-yet-underadopted techniques; and (ii) porting optimizers from one domain (e.g., LLM jailbreak) to new domains (e.g., corpus-poisoning
embedding model). In all, TROPT significantly lowers the barrier to adopting and advancing discrete text optimization.
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Cryptography and Security · Cross-listed from cs.SE
An Automated Framework for Input Alphabet Construction in Stateful Protocol Implementation Learning
JiongHan Wang and WenChao Huang
As a prevalent analytical technique for stateful protocol implementations, state machine learning suffers from a core bottleneck stemming from handcrafted input alphabets. Manual alphabet definition inherently limits the completeness of input exploration, making it difficult to capture anomalous non-conformant messages and consequently missing latent semantic defects. In this paper, we target automatic input alphabet generation to break the above limitation for state machine learning. We adopt large
language models to parse protocol message layouts and produce candidate input symbols following structured mutation rules, which automatically covers valid and invalid message spaces and eliminates reliance on manual protocol expertise. Considering the rising overhead brought by continuously growing alphabets, we introduce a mini-batch incremental learning strategy to reuse existing learned automata when incorporating new alphabet entries. Comprehensive experiments on practical protocol stacks indicate our approach can reproduce existing security vulnerabilities and identify novel semantic bugs. A subset of these newly discovered issues has been confirmed and patched by developers, proving the practicability and effectiveness of our proposed method.
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Cryptography and Security
Detecting Malicious Agent Skills in the Wild using Attention
Bacem Etteib, Daniele Lunghi and Tégawendé F. Bissyandé
LLM
agents increasingly load skills, file-based packages of natural-
language instructions written by third parties and distributed through marketplaces, that execute with the user's privileges. A single malicious skill can exfiltrate data, hijack the
agent, or persist as a supply-chain foothold, which turns the skill marketplace into a new attack surface for agentic systems.
Prompt-injection defenses do not carry over to this setting. They rely on a boundary between trusted instructions and untrusted data, whereas a skill is itself a body of instructions, so an injected command sits among many legitimate ones and inherits their authority. We present Locate-and-Judge, a two-stage detector designed for this regime. A lightweight locator scores the structural spans of a skill by the instruction-following
attention each span draws and retains only the top-K. A judge then examines the retained spans in detail. Concentrating the costly judgment on a few high-
attention spans lets the detector audit an entire marketplace instead of a sample. Compared to direct LLM-based scanning, this approach offers an order-of-magnitude cost reduction, dramatically increasing its scalability at a small cost to recall, and it dominates keyword and regex baselines at comparable expense. Deployed at marketplace scale and at negligible cost, Locate-and-Judge flags skills with high precision, the majority of which we manually confirmed as malicious, surfacing dozens of live malicious skills, including several disguised as benign functionality and many that SkillSpector and Cisco Skill Scanner fail to detect. We release the resulting labeled
dataset.
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Cryptography and Security
OptChain: Achieving Optimal Throughput of Permissionless Blockchains
Chunjiang Che, Songze Li and Xuechao Wang
We introduce OptChain, a permissionless blockchain state machine replication (SMR) protocol that achieves optimal throughput. We first establish a theoretical upper bound on the throughput of any SMR protocol under a fixed error probability, and OptChain is the first protocol to approach this limit. Conceptually, OptChain is a sharding protocol that optimizes both vertical and horizontal scalability. Vertically, we introduce Shardis, a novel permissionless verifiable information dispersal mechanism that maximizes intra-shard throughput to its physical limit, determined by the fastest node's bandwidth within each shard. Horizontally, we propose
diffusion mining, which ensures security as long as each shard includes at least one honest node, thereby allowing for the maximum number of shards. We provide a formal security and efficiency analysis, demonstrating that OptChain approaches the established upper bound while maintaining robust security. Finally, we implement a full prototype of OptChain and deploy it on AWS EC2 nodes across various regions. Experimental results indicate that OptChain outperforms state-of-the-art permissionless protocols and closely approaches the theoretical optimal throughput.
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Cryptography and Security
FlexServe: A Fast and Secure LLM Serving System for Mobile Devices with Flexible Resource Isolation
Yinpeng Wu, Yitong Chen, Lixiang Wang et al. (+3 more)
Device-side Large
Language Models (LLMs) have grown explosively, offering stronger
privacy and higher availability than their cloud-side counterparts. During LLM inference, both the model weights and the user data are valuable, and attackers may compromise the OS kernel to steal them. ARM TrustZone is the de facto hardware-based isolation technology on mobile devices, used to protect sensitive applications from a compromised OS. However, protecting LLM inference with TrustZone incurs significant overhead to both the secure inference and the normal aplications, due to two challenges: the inflexible resource isolation and the inefficient secure resource management. To address these challenges, this paper presents FlexServe, a fast and secure LLM inference system for mobile devices. The key idea is to decouple the access permission from the management permission of secure resources, so that the normal-world OS cannot access them but can still manage them as usual. First, FlexServe introduces a Recallable Resource Isolation mechanism to construct Recallable Secure
Memory (Flex-Mem) and a Recallable Secure NPU (Flex-NPU). They can only be accessed by the secure world, but can be efficiently allocated and reclaimed by the normal-world OS. Based on them, FlexServe further introduces a FlexServe Framework to run secure LLM inference in the secure world. It works together with the normal-world OS to perform cooperative secure
memory management. We implement a prototype of FlexServe and compare it with two TrustZone-based strawman designs. The results show that FlexServe achieves average TTFT speedups of 10.05X over the strawman and 2.44X over an optimized strawman.
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All authors Yinpeng Wu, Yitong Chen, Lixiang Wang, Jinyu Gu, Zhichao Hua, Yubin Xia
Cryptography and Security
TooBad: Backdoor Diffusion Models with Ultra-Low Poison Rate and Imperceptible Trigger
Vu Tuan Truong and Long Bao Le
Diffusion models (DMs), despite their impressive capabilities across a wide range of generative tasks, have been shown to be vulnerable to
backdoor attacks. However, existing
backdoor methods face critical trade-offs among key factors: attack performance, stealthiness, time complexity, and required poison rates. For example, achieving high attack performance typically demands a high poison rate and prolonged training, which undermines stealthiness, making the attack more detectable by
backdoor defenses. This paper proposes TooBad (trigger optimization for
backdoor diffusion models), a
backdoor framework which introduces a novel DM-tailored trigger optimization technique to dramatically enhance the performance of
backdoor attacks on DMs. Experiments on representative
benchmarks such as CIFAR-10 show that TooBad can achieve high ASRs ($> 85$%) at only 0.5% poison rate, significantly lower than the 10% typically required by prior work on the same
datasets. At 5% poison rate, TooBad reaches nearly 100% ASR within just 3-5
backdoor injection epochs, whereas existing methods need at least 30-50 epochs at double the poison rate for comparable results. Despite its potency, TooBad easily evades SOTA defenses and maintains high utility. These results reveal a critical threat on DMs and highlight the need for more robust defenses against such stealthy yet efficient attacks.
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Cryptography and Security · Cross-listed from cs.LG
Exposing the Illusion of Erasure in Knowledge Editing for LLMs
Advik Raj Basani and Anshuman Chhabra
Knowledge Editing (KE) has emerged as a frontier for updating specific facts in LLMs without costly retraining, but its reliability and underlying mechanisms remain poorly understood. In this work, we examine KE from an
adversarial elicitation perspective, revealing that edited knowledge is often not fully erased and continues to surface, with consistent failures observed across diverse model architectures. To explain this behavior, we conduct a mechanistic analysis of popular KE methods. We show that low-rank updates do not overwrite existing knowledge but instead redistribute it within the model's representation space. Furthermore, we find that these methods act as targeted suppression mechanisms that reduce the likelihood of expressing original facts, rather than removing them from the model. Analysis of the loss landscape reveals that edited knowledge lies in narrow, anisotropic regions that are highly sensitive to perturbations, making them highly vulnerable to indirect prompting and
adversarial attacks. By exposing these profound architectural vulnerabilities, our work proves that KE
algorithms are inherently bypassable and motivates a fundamental reevaluation of how we deploy post-hoc updates in several LLM applications.
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Cryptography and Security · Cross-listed from quant-ph
Quantum Key Distribution Without Shared Reference Frame Under Unital Noise
Junaid ur Rehman, Shehbaz Tariq and Symeon Chatzinotas
We consider a general and practical scenario of
quantum key distribution (QKD) over an unknown, stationary, unital
qubit channel. Furthermore, due to practical limitations, e.g., relative movement and rotation of communicating parties, a global shared reference frame cannot be established. This scenario can routinely appear in satellite QKD. We propose two methods to overcome the physical
qubit noise and the lack of shared reference frame. The first proposed approach involves constructing the Pauli transfer
matrix (PTM) description of the channel, which we achieve without requiring a shared reference frame, by absorbing the lack of shared reference frame in the channel definition. This is followed by the identification of singular vectors of PTM as the Bloch vectors for optimal signal states. In the optimized local bases, the resulting correlations are equivalent, up to outcome relabeling, to those of a Pauli channel, allowing us to show the optimality of the BB84 and six-state QKD protocols under these conditions. The second approach, called the sequential basis matching (SBM) involves sequentially identifying the channel-optimized local bases that enable QKD. We show that both of these approaches result in the same effective key exchange rate for QKD.
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Cryptography and Security
A Hybrid Intrusion Detection System for Electric Vehicle Charging Infrastructure
Charukeshi Joglekar, Chijioke Eze, Danni Xiang et al. (+1 more)
The integration of Electric Vehicle Charging Stations (EVCSs) into the smart grid necessitates sophisticated digital infrastructure for their management and coordination, which expands the attack surface and makes both the power grid and EVCSs vulnerable to cyberattacks. This research addresses critical gaps in existing EVCS Intrusion Detection Systems (IDS) by proposing a hybrid IDS that integrates attack detection on both the cyber and physical layer of the EVCS ecosystem. The proposed hybrid IDS utilizes a dual-layer integration method, which combines network-based IDS (NIDS) and host-based IDS (HIDS). This approach facilitates for comprehensive monitoring of both network traffic through the NIDS and host-level activities via the HIDS, effectively addressing the unique challenges posed by the interconnected nature of EVCS ecosystems. Utilizing the recent CICEVSE2024
dataset, the IDS presented in this work performs multiclass classification across various attack types, including False Data Injection Attacks (FDIAs), reconnaissance, denial of service,
backdoor, and cryptojacking attacks. Experimental results demonstrate that our approach achieves excellent detection accuracy, with the NIDS component reaching 99.99% accuracy for network-based attacks and the HIDS component achieving 83.47% accuracy on FDIA, cryptojacking,
backdoor, all DoS, all Recon except Slowloris Scan attacks. This dual-layer detection significantly outperforms single-source detection approaches previously presented in literature.
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All authors Charukeshi Joglekar, Chijioke Eze, Danni Xiang, Antonello Monti