arXiv:2602.03284cs.CRcs.CV2026-02中稿 · ICLR被引 6

通过重调脉冲时间攻击脉冲神经网络,隐蔽性强且效果显著。

Time Is All It Takes: Spike-Retiming Attacks on Event-Driven Spiking Neural Networks

  • 设计基于时间的脉冲重调攻击,保持脉冲数量和强度不变
  • 在DVS-Gesture上成功率超90%,仅影响不到2%的脉冲
  • 适用于评估事件驱动神经网络的时间鲁棒性,适合安全研究者

脉冲神经网络(SNN)以离散脉冲计算并利用时间结构,但多数对抗攻击改变的是强度或事件数量,而非时间。本文研究一种仅改变脉冲时间的对手:在不改变脉冲计数和幅度的前提下,重调现有脉冲的时间,实现速率保持。我们形式化了一个容量为1的脉冲重调威胁模型,采用统一三类预算:单脉冲抖动 $\/mathcal{B}_{\\infty}$、总延迟 $\/mathcal{B}_{1}$、篡改次数 $\/mathcal{B}_{0}$。可行的对抗样本必须满足时间线一致性与无重叠,导致搜索空间离散且受限。为实现大规模优化,提出投影式环内(PIL)优化:通过概率位移逻辑实现可微分的软重调用于反向传播,前向传递中严格投影生成满足容量-1、无重叠及预算约束的可行离散调度。目标函数最大化投影输入的任务损失,并加入容量正则项与预算感知惩罚,稳定梯度并使优化对齐评估。我们在事件驱动基准(CIFAR10-DVS、DVS-Gesture、N-MNIST)和多种SNN架构上进行测试,涵盖二值与整数事件网格及不同重调预算,并评估了针对时间感知对抗训练的防御模型。例如,在DVS-Gesture上,攻击成功率超过90%,且$\/mathcal{B}_{0}$下影响的脉冲少于2%。结果表明,脉冲重调是当前防御难以应对的实用且隐蔽的攻击面,为事件驱动SNN的时间鲁棒性提供了明确参考。代码已公开于https://github.com/yuyi-sd/Spike-Retiming-Attacks。

原文摘要 · Abstract (English)

Spiking neural networks (SNNs) compute with discrete spikes and exploit temporal structure, yet most adversarial attacks change intensities or event counts instead of timing. We study a timing-only adversary that retimes existing spikes while preserving spike counts and amplitudes in event-driven SNNs, thus remaining rate-preserving. We formalize a capacity-1 spike-retiming threat model with a unified trio of budgets: per-spike jitter $\mathcal{B}_{\infty}$, total delay $\mathcal{B}_{1}$, and tamper count $\mathcal{B}_{0}$. Feasible adversarial examples must satisfy timeline consistency and non-overlap, which makes the search space discrete and constrained. To optimize such retimings at scale, we use projected-in-the-loop (PIL) optimization: shift-probability logits yield a differentiable soft retiming for backpropagation, and a strict projection in the forward pass produces a feasible discrete schedule that satisfies capacity-1, non-overlap, and the chosen budget at every step. The objective maximizes task loss on the projected input and adds a capacity regularizer together with budget-aware penalties, which stabilizes gradients and aligns optimization with evaluation. Across event-driven benchmarks (CIFAR10-DVS, DVS-Gesture, N-MNIST) and diverse SNN architectures, we evaluate under binary and integer event grids and a range of retiming budgets, and also test models trained with timing-aware adversarial training designed to counter timing-only attacks. For example, on DVS-Gesture the attack attains high success (over $90\%$) while touching fewer than $2\%$ of spikes under $\mathcal{B}_{0}$. Taken together, our results show that spike retiming is a practical and stealthy attack surface that current defenses struggle to counter, providing a clear reference for temporal robustness in event-driven SNNs. Code is available at https://github.com/yuyi-sd/Spike-Retiming-Attacks.

脉冲神经网络对抗攻击时间鲁棒性事件驱动

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