Promoting Data and Model Privacy in Federated Learning through Quantized LoRA
JianHao Zhu, Changze Lv, Xiaohua Wang, Muling Wu, Wenhao Liu, Tianlong Li, Zixuan Ling, Cenyuan Zhang, Xiaoqing Zheng, Xuanjing Huang
TL;DR
FedLPP tackles simultaneous data privacy and model IP protection in federated learning for large language models by distributing a quantized proxy of LoRA adapters to clients, enabling gradient updates without exposing a strong global model. It combines quantization with LoRA-based PEFT to reduce communication while preserving training effectiveness. The empirical results across multiple datasets and model sizes show FedLPP outperforms the baseline FedSP while maintaining privacy and achieving comparable performance to non-private baselines in many settings. This approach offers a practical, resource-efficient path toward privacy-preserving FL for commercial LLM deployments.
Abstract
Conventional federated learning primarily aims to secure the privacy of data distributed across multiple edge devices, with the global model dispatched to edge devices for parameter updates during the learning process. However, the development of large language models (LLMs) requires substantial data and computational resources, rendering them valuable intellectual properties for their developers and owners. To establish a mechanism that protects both data and model privacy in a federated learning context, we introduce a method that just needs to distribute a quantized version of the model's parameters during training. This method enables accurate gradient estimations for parameter updates while preventing clients from accessing a model whose performance is comparable to the centrally hosted one. Moreover, we combine this quantization strategy with LoRA, a popular and parameter-efficient fine-tuning method, to significantly reduce communication costs in federated learning. The proposed framework, named \textsc{FedLPP}, successfully ensures both data and model privacy in the federated learning context. Additionally, the learned central model exhibits good generalization and can be trained in a resource-efficient manner.
