DeepU: Deeper Granular Within-Layer Machine Unlearning

Abstract

Machine unlearning (MU) aims to remove the influence of selected data from trained models, offering an efficient alternative to full retraining. With the rise of increasingly stringent privacy regulations, including the right to be forgotten, machine learning models must incorporate mechanisms that ensure compliance while preserving performance. However, existing MU methods often suffer from performance degradation, and limited granularity, leaving residual traces that adversaries can exploit. We propose DeepU, a fine-grained unlearning framework that performs within-layer, weight-level analysis and quantifies the influence of individual weights using the signal-to-noise ratio (SNR) derived from the gradients of sensitive and non-sensitive data. DeepU categorizes weights as influential, intra-dependent, or non-influential and applies targeted weight updates: resetting or perturbing influential weights, decaying intra-dependent ones, and stabilizing the remaining ones via limited backpropagation. We evaluated DeepU on standard datasets including CIFAR-10, CIFAR-100, Tiny ImageNet, and CelebA, demonstrating a 60–90% reduction in successful membership inference attacks with less than a 3% drop in accuracy, significantly outperforming existing benchmark methods. Re-tuning requires only 20.75 seconds and 102.47 MB, making DeepU up to 36.6 times faster than competing methods. We further evaluate robustness against Generative Adversarial Network (GAN) and diffusion-based model inversion attacks across white-box, black-box, and label-only threat models, demonstrating that DeepU consistently reduces reconstruction of forgotten data.