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Computer Engineering ›› 2026, Vol. 52 ›› Issue (9): 306-319. doi: 10.19678/j.issn.1000-3428.0252239

• Cyberspace Security • Previous Articles     Next Articles

Learnable Trigger Backdoor Attacks for Federated Learning

LIU Tao, MAN Dapeng*(), XU Chen, Lü Jiguang, FENG Zhu, ZENG Fanyi, ZHOU Xue, YANG Wu   

  1. College of Computer Science and Technology, Harbin Engineering University, Harbin 150001, Heilongjiang, China
  • Received:2025-03-18 Revised:2025-05-19 Online:2026-09-15 Published:2026-09-01
  • Contact: MAN Dapeng

面向联邦学习的可学习触发器后门攻击

刘涛, 苘大鹏*(), 许晨, 吕继光, 冯驻, 曾凡一, 周雪, 杨武   

  1. 哈尔滨工程大学计算机科学与技术学院, 黑龙江 哈尔滨 150001
  • 通讯作者: 苘大鹏
  • 作者简介:

    刘涛(CCF学生会员), 男, 博士研究生, 主研方向为分布式人工智能安全

    苘大鹏(通信作者), 教授、博士

    许晨, 讲师、博士

    吕继光, 副教授、博士

    冯驻, 硕士研究生

    曾凡一, 博士研究生

    周雪, 博士研究生

    杨武, 教授、博士

  • 基金资助:
    国家自然科学基金面上项目(62272127); NSFC-企业联合基金重点项目(U20B2048); NSFC-企业联合基金重点项目(U21B2019); NSFC-区域联合基金重点项目(U22A2036); 黑龙江省自然科学基金研究团队项目(TD2022F001); 中央高校基本科研业务费专项资金(3072024XX0606)

Abstract:

Conventional clean label backdoor attacks often fail to establish a strong link between the trigger and target classes, resulting in a low Attack Success Rate (ASR). Extensive experimental evidence shows that this failure is even more severe in Federated Learning (FL). The main reason for attack failure is that the random selection of the trigger causes it to lack a direct connection with the target class. To this end, a learnable trigger backdoor attack is designed for FL, which fully utilized the task information and shared model issued by the central server to train a trigger that is strongly correlated with the target class. This training process is formalized into a dual-objective optimization problem and solved. The optimal perturbation under constraint conditions is found to blur the original features of the image as much as possible, thereby maximizing the model's learning ability for the trigger. Subsequently, these blurred images are trained by adding the triggers allowed within the specified range as inputs, minimizing their image classification loss and generating the optimal trigger quickly using the optimization method of small-batch Projected Gradient Descent (PGD). The backdoor attack activated by this trigger guarantees excellent attack performance in FL. The experimental results on three datasets show that the ASR of the proposed method in FL is much higher than that of all types of existing clean-label backdoor attacks, especially on CIFAR-10, which shows an improvement of more than 82 percentage points compared to the baseline method. The proposed attack method presents new challenges for the security of FL.

Key words: machine learning, Federated Learning (FL), backdoor attack, clean label attack, learnable trigger

摘要:

传统的干净标签后门攻击通常无法在触发器和目标类之间建立有效的强连接关系, 导致攻击成功率(ASR)降低。大量实验结果表明, 这种失效现象在联邦学习(FL)中更加严重。攻击失败的主要原因在于触发器的随机选择使其缺少和目标类的直接联系。为此, 面向FL设计一种可学习触发器后门攻击, 充分利用中心服务器下发的任务信息和共享模型训练与目标类强相关的触发器, 将该训练过程形式化为双目标优化问题并求解。在约束条件下找到最佳扰动尽可能模糊图像的原始特征, 从而最大化模型对触发器的学习能力; 然后对这些模糊图像添加规定范围内允许的触发器作为输入进行训练, 最小化其图像分类损失并利用小批量投影梯度下降(PGD)的优化方法快速生成最优触发器。利用该触发器激活的后门攻击在FL中仍能保证出色的攻击性能。在3个数据集上的实验结果表明, 所提方法在FL中攻击成功率远高于现有的各类干净标签后门攻击, 尤其在CIFAR-10上其ASR相较于基线方法提升了约82百分点, 所提出的攻击方法对FL的安全性提出了新的挑战。

关键词: 机器学习, 联邦学习, 后门攻击, 干净标签攻击, 可学习触发器