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

Fuente: arXiv
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Main Authors: Wang, Tiantong, Yan, Xinyu, Wu, Tiantong, Hao, Yurong, Xie, Pengjun, Lim, Wei Yang Bryan
Format: Preprint
Published: 2026
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author Wang, Tiantong
Yan, Xinyu
Wu, Tiantong
Hao, Yurong
Xie, Pengjun
Lim, Wei Yang Bryan
author_facet Wang, Tiantong
Yan, Xinyu
Wu, Tiantong
Hao, Yurong
Xie, Pengjun
Lim, Wei Yang Bryan
contents 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, with most algorithms' average degradation well below 1% up to 10% noise, and can even outperform the noise-free baseline for some algorithms under 1% noise. Code is available at https://github.com/Tristan0318/MPU.
format Preprint
id arxiv_https___arxiv_org_abs_2602_23798
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MPU: Towards Secure and Privacy-Preserving Knowledge Unlearning for Large Language Models
Wang, Tiantong
Yan, Xinyu
Wu, Tiantong
Hao, Yurong
Xie, Pengjun
Lim, Wei Yang Bryan
Machine Learning
Artificial Intelligence
Cryptography and Security
Distributed, Parallel, and Cluster Computing
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, with most algorithms' average degradation well below 1% up to 10% noise, and can even outperform the noise-free baseline for some algorithms under 1% noise. Code is available at https://github.com/Tristan0318/MPU.
title MPU: Towards Secure and Privacy-Preserving Knowledge Unlearning for Large Language Models
topic Machine Learning
Artificial Intelligence
Cryptography and Security
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2602.23798