Achieving Privacy-preserving Federated Learning with Irrelevant Updates over E-Health Applications

Abstract

The widespread use of edge devices in E-Health such as smartphones and wearables means richer electronic health records (EHR) are becoming available. Training deep learning models on these data can effectively improve the quality of healthcare services. Recently, federated learning (FL) has received extensive attention in E-Health because it can train a model by only sharing gradients without disclosing the original EHR of owners. In this case, however, the adversary can still violate EHR owners' privacy based on shared gradients. To mitigate privacy threat, several privacy-preserving FL protocols have been proposed by utilizing different cryptography techniques. Unfortunately, existing privacy-preserving FL schemes do not take into account irrelevant updates, which are useless for the convergence of the global model. This may reduce the predictive accuracy and worse may lead to the uselessness of the final model. In this paper, we propose PFL-IU, an efficient and privacy-preserving FL framework that is compatible with irrelevant updates. Specifically, we first design a communication-efficient secure aggregation protocol by using a non-interactive key generation algorithm. Then we present a sign method to mitigate the negative impact incurred by irrelevant updates, which will accelerate model convergence and improve predictive accuracy. Moreover, PFL-IU is robust to EHR owners' dropout during the whole training phase. Extensive experiments using the real-world dataset demonstrate that PFL-IU can achieve better performance in terms of accuracy, convergence and efficiency.