Privacy-Preserving Federated Averaging on Heterogeneous Data
摘要
Federated learning (FL) has becoming a prevailing paradigm which enables small-scale devices to collaboratively learn a shared model efficiently and trains a machine learning model without exchanging data. However, though the original data never leave the local machines in federated learning, possible privacy leakage still exists. To make strong privacy guarantee, in this paper, we incorporate the notion of differential privacy (DP) to study the federated averaging (FedAvg) algorithm. In particular, by adding calibrated gaussian noise, we propose a set of differentially private federated averaging algorithms (DP-FedAvg) under the full and partial participation schemes. We provide tight analysis of the privacy bound by using advanced composition and privacy amplification techniques. We also analyze the convergence bound of DP-FedAvg without having the assumptions: (i) the data are the independent identically distribution (IID), and (ii) all the devices are active. It turns out that the convergence rate is consistent with the one without DP guarantee. The effectiveness of our algorithms is demonstrated by synthetic and real datasets.