[2602.23798] MPU: Towards Secure and Privacy-Preserving Knowledge Unlearning for Large Language Models

Computer Science > Machine Learning arXiv:2602.23798 (cs) [Submitted on 27 Feb 2026] Title:MPU: Towards Secure and Privacy-Preserving Knowledge Unlearning for Large Language Models Authors:Tiantong Wang, Xinyu Yan, Tiantong Wu, Yurong Hao, Yong Jiang, Fei Huang, Wei Yang Bryan Lim View a PDF of the paper titled MPU: Towards Secure and Privacy-Preserving Knowledge Unlearning for Large Language Models, by Tiantong Wang and 6 other authors View PDF HTML (experimental) Abstract:Machine unlearning for large language models often faces a privacy dilemma in which strict constraints prohibit sharing either the server's parameters or the client's forget set. To address this dual non-disclosure constraint, we propose MPU, an algorithm-agnostic privacy-preserving Multiple Perturbed Copies Unlearning framework that primarily introduces two server-side modules: Pre-Process for randomized copy generation and Post-Process for update aggregation. In Pre-Process, the server distributes multiple perturbed and reparameterized model instances, allowing the client to execute unlearning locally on its private forget set without accessing the server's exact original parameters. After local unlearning, the server performs Post-Process by inverting the reparameterization and aggregating updates with a harmonic denoising procedure to alleviate the impact of perturbation. Experiments with seven unlearning algorithms show that MPU achieves comparable unlearning performance to noise-free baselines, wi...