Optimal Defenses Against Gradient Reconstruction Attacks

Federated Learning (FL) is designed to prevent data leakage through collaborative model training without centralized data storage. However, it remains vulnerable to gradient reconstruction attacks that recover original training data from shared gradients. To optimize the trade-off between data leakage and utility loss, we first derive a theoretical lower bound of reconstruction error (among all attackers) for the two standard methods: adding noise, and gradient pruning. We then customize these two defenses to be parameter-and model-specific and achieve the optimal trade-off between our obtained reconstruction lower bound and model utility. Experimental results validate that our methods outperform Gradient Noise and Gradient Pruning Figure 1: DP-SGD treats all parameters with the same vulnerability, by protecting the training data better while also achieving while our method distinguishes the vulnerability better utility. The code for this project is available here. of each parameter and designs a customized defense strategy.