Netinfo Security ›› 2026, Vol. 26 ›› Issue (10): 1595-1615.doi: 10.3969/j.issn.1671-1122.2026.10.007

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Privacy-preserving and anti-poisoning method for hierarchical federated learning

Liu Yuanxin, Liang Yihuai(), Zhou Zhengchun   

  1. School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China
  • Received:2026-02-04 Online:2026-10-10 Published:2026-11-06
  • Contact: Liang Yihuai E-mail:liangyh@swjtu.edu.cn

Abstract:

Federated learning (FL) as a privacy-preserving distributed machine learning paradigm has been widely applied across various fields. However, traditional single-server architectures face issues of excessive server communication overhead as user devices increase. Although multi-edge-server architectures alleviate the single-point load pressure, their limited coverage cannot meet the demands of large-scale FL for data diversity and model generalization capability. In recent years, the hierarchical federated learning (HFL) architecture has been introduced, which incorporates edge servers in different regions to perform intermediate aggregation while a cloud server handles global aggregation. This approach effectively reduces the cloud server’s load and is better suited for large-scale FL training across multiple regions. Nevertheless, HFL still faces challenges such as privacy leakage and poisoning attacks, especially in non-independent and identically distributed (non-IID) data scenarios. Moreover, the unreliability of edge servers in the intermediate layer is often overlooked, which can easily lead to collusion and crash risks, thereby threatening privacy security and affecting model training. To address these issues, this paper proposed a secure and reliable aggregation scheme based on the HFL architecture. Firstly, by using Shamir’s secret sharing and a masking mechanism, the scheme not only enhanced privacy protection during the training phase but also significantly improves the system’s tolerance to collusion and crash at edge servers. Secondly, the paper integrated Gaussian mixture model clustering and a scaled dot-product attention mechanism to design an anti-poisoning protocol under privacy protection. Theoretical analysis proves that the proposed scheme offers strong reliability in terms of privacy protection and resilience against edge server collusion and crash risks. Extensive experiments show that the scheme effectively resists poisoning attacks on various datasets and under non-IID settings, improving model accuracy by 5% to 20% compared to state-of-the-art methods.

Key words: hierarchical federated learning, privacy-preserving, anti-poisoning, collusion attack, crash risk

CLC Number: