Skip to content

SW-ProxyCE: Zero-Query Adversarial Transfer from Public EEG Encoders to Private Downstream Models

Aug 2026 · 0 citations · 28 references
Computer Science

TL;DR

Shrinkage-Whitened Proxy Cross-Entropy (SW-ProxyCE), a query-free task-aware attack framework that recovers task-level decision geometry from a small labeled reference set through shrinkage-whitened class prototypes, enabling transferable adversarial generation without training an additional surrogate classifier is proposed.

Abstract

Electroencephalography (EEG) foundation models have recently emerged as a promising paradigm for EEG decoding by learning reusable representations from large-scale heterogeneous neural recordings. However, the open release of EEG foundation encoders, while facilitating downstream developments, also introduces a previously unexplored security risk: publicly available representations may make private downstream models vulnerable. This paper investigates adversarial transfer attacks in EEG foundation model deployment in a public-encoder and private-downstream setting, where attackers have white-box access to a released encoder and a small task-matched labeled reference set, but no access or query to victim parameters, outputs, or gradients. We propose Shrinkage-Whitened Proxy Cross-Entropy (SW-ProxyCE), a query-free task-aware attack framework that recovers task-level decision geometry from a small labeled reference set through shrinkage-whitened class prototypes, enabling transferable adversarial generation without training an additional surrogate classifier. We evaluated SW-ProxyCE across three EEG tasks using three general-purpose foundation encoders and a paradigm-specific pre-trained encoder, covering both linear-probing and full-fine-tuning downstream models in cross-subject and within-subject scenarios. Results demonstrated that adversarial examples generated from the public encoder and limited labeled references can effectively transfer to inaccessible downstream models. SW-ProxyCE consistently outperformed task-agnostic representation-shift attacks, revealing that the strong transferability of EEG foundation models does not necessarily lead to adversarial robustness. Our code will be available on GitHub.

View source

Similar papers

Aug 2026

FDT-PC: Enhancing Adversarial Transferability through Frequency Domain Transformation and Perceptual Constraints

FDT-PC (Frequency Domain Transformation with Perceptual Constraints), a novel method that enhances adversarial transferability across different model architectures, is proposed, which achieves superior black-box attack performance on both CNNs and Vision Transformers, outperforming existing state-of-the-art input transformation methods.

Bo Li, Li Tang, Xin Jin et al. · 0 citations
Preprint Jul 2026

Dual Adversarial Fine-tuning for Enhancing Robustness of Large Vision Language Model

While Large Vision-Language Models (LVLMs), represented by LLaVA and GPT-4V, have demonstrated remarkable capabilities, their visual inputs remain vulnerable to adversarial attacks, posing significant security risks. Existing defense methods predominantly target single-task scenarios (e.g., zero-shot classification) and consequently lack generalizability across various multimodal tasks. To address this limitation, we propose a dual adversarial fine-tuning framework that jointly optimizes visual and semantic supervision signals from two modalities, enhancing model robustness while generalizing across multiple downstream tasks. The proposed framework comprises two core components, i.e., $\textbf{Visual}$ supervision branch and $\textbf{Semantic}$ supervision branch. The former branch leverages features from clean images, extracted via a frozen original vision encoder, to guide adversarial robustness while the latter incorporates caption-image alignment as a contextual signal to preserve semantic coherence under attack. Moreover, our method achieves cross-task robustness by simply replacing the CLIP vision encoder in the original model, with no need of separate task-specific retraining or architecture modifications.Extensive experiments demonstrate that our approach outperforms the state-of-the-art method in adversarial robustness evaluation across zero-shot classification, image captioning, and visual question answering (VQA) tasks.

Sibo Wang, Jie Zhang, Shiguang Shan et al. · 0 citations

Parameter-Efficient Dual-Loss Adaptation with Logit Divergence: A Unified Approach for Adversarial Example Detection and Robust Inference

D3Adapter is presented, a threat-aware framework that unifies adversarial example detection (AED) and robust inference and scalability across datasets with varying numbers of classes is studied, showing that unified detection and robust inference can be achieved with predictable overhead proportional to the number of adapters.

Zirui Fu, Marco Donato · 0 citations
Open access Aug 2026

A Novel Adversarial Approach for EEG Dataset Refinement: Enhancing Generalization Through Proximity-to-Boundary Scoring.

As deep learning (DL) performs remarkably in pattern recognition from complex data, it is used to interpret user intentions from electroencephalography (EEG) signals. However, the DL models trained on EEG datasets have low generalization ability owing to numerous noisy samples in datasets. Therefore, prior research has focused on distinguishing and eliminating noisy samples from datasets. One intuitive solution is based on the property of noisy samples during the training phase. Noisy samples are located near the decision boundary after model training. Therefore, they can be detected using a gradient-based adversarial attack. However, the limitations of usability exist because the intuitive solution requires additional hyperparameter optimizations, resulting in a tradeoff between accurateness and efficiency. In this article, we proposed a novel training framework that enhances the generalization ability of the model by reducing the influence of noisy samples during training, without additional hyperparameter optimizations. We designed the proximity-to-boundary score (PBS) to continuously measure the data closeness to the decision boundary. As a result, the proposed framework improved the generalization ability of the model across two motor imagery datasets and one sleep stage dataset. Specifically, training the model with the proposed framework resulted in performance improvements ranging from a minimum of 1.43% to a maximum of 6.66% on two motor imagery datasets and from a minimum of 0.72% to a maximum of 2.85% on a sleep stage classification dataset. We qualitatively confirmed that data with low PBS are indeed noisy samples and degrade the model training. Hence, we demonstrated that employing the proposed framework accurately and efficiently mitigates the influence of noisy samples, enhancing the model's generalization capabilities.

Sung-Jin Kim, Heejo Kong, Dae-Hyeok Lee et al. · 0 citations
Preprint Aug 2026

ArmorOCR: Grounded Adversarial Visual Perception via Observation-Transferred Self-Distillation

Large multimodal models (LMMs) have demonstrated strong OCR recognition capabilities, yet remain vulnerable to adversarial visual text that is readable to humans but challenging for models to localize and recognize. Existing OCR benchmarks mainly focus on natural or document-style text, while adversarial OCR evaluations remain limited in scale, task coverage, or region-aware evaluation. In this paper, we formulate adversarial OCR as a \textbf{grounded OCR perception} task and introduce \textbf{AdvSpot}, the first benchmark for grounded adversarial OCR evaluation. AdvSpot comprises 390 images with region-level annotations, spanning 5 primary categories and 13 fine-grained adversarial OCR types. To address this challenge, we propose \textbf{ArmorOCR}, a two-stage training framework for robust adversarial OCR perception. ArmorOCR first acquires missing adversarial OCR perception from privileged transformed observations through On-Policy Self-Distillation (OPSD), and then refines grounded OCR perception through Group Relative Policy Optimization (GRPO) with task-conditioned rewards for localization, recognition, full spotting, and visual question answering (VQA). Experiments on our AdvSpot, other adversarial OCR benchmarks, and general OCR benchmarks demonstrate that ArmorOCR consistently improves adversarial OCR perception while preserving competitive general OCR capability.

Linhan Cao, Siyuan Li, Jun Lan et al. · 0 citations

Related blog posts

MIT News · Artificial Intelligence Aug 27, 2026

Looking beyond natural sequences

A new machine-learning framework aims to improve the success rate of computational protein design while moving away from results that reproduce sequences found in nature.