Deep Face Leakage: Inverting High-Quality Faces From Gradients Using Residual Optimization

Collaborative learning has gained significant traction for training deep learning models without sharing the original data of participants, particularly when dealing with sensitive data such as facial images. However, current gradient inversion attacks are employed to progressively reconstruct private data from gradients, and they have shown successful in extracting private training data. Nonetheless, our observations reveal that these methods exhibit suboptimal performance in face reconstruction and result in the loss of numerous facial details. In this paper, we propose DFLeak, an effective approach to boost face leakage from gradients using residual optimization and thwart the privacy of facial applications in collaborative learning. In particular, we first introduce a superior initialization method to stabilize the inversion process. Second, we propose to integrate prior-free face restoration (PFFR) results into the gradient inversion optimization process in a residual manner, which enriches facial details. We further design a pixel update schedule to mitigate the adverse effects of image regularization terms and preserve fine facial details. Comprehensive experimentation demonstrates the effectiveness of our approach in achieving more realistic and higher-quality facial image reconstructions, surpassing the performance of state-of-the-art gradient inversion attacks.