Federated learning enables learning from decentralized data sources without compromising privacy, which makes it a crucial technique. However, it is vulnerable to model poisoning attacks, where malicious clients interfere with the training process. Previous defense mechanisms have focused on the server-side by using careful model aggregation, but this may not be effective when the data is not identically distributed or when attackers can access the information of benign clients. In this paper, we propose a new defense mechanism that focuses on the client-side, called FedDefender, to help benign clients train robust local models and avoid the adverse impact of malicious model updates from attackers, even when a server-side defense cannot identify or remove adversaries. Our method consists of two main components: (1) attack-tolerant local meta update and (2) attack-tolerant global knowledge distillation. These components are used to find noise-resilient model parameters while accurately extracting knowledge from a potentially corrupted global model. Our client-side defense strategy has a flexible structure and can work in conjunction with any existing server-side strategies. Evaluations of real-world scenarios across multiple datasets show that the proposed method enhances the robustness of federated learning against model poisoning attacks.

分散化数据源的联邦学习为学习提供隐私保护，但容易受到恶意客户干扰的模型中毒攻击，因此本文提出了一种名为FedDefender的新客户端防御机制，通过攻击容忍的本地元更新和攻击容忍的全局知识蒸馏两个组件，实现对联邦学习的模型中毒攻击的抵御和知识提取，从而提高其鲁棒性。

FedDefender：客户端抗攻击的联邦学习