arXiv Machine Learning

Exact Federated Continual Unlearning for Ridge Heads on Frozen Foundation Models

arXiv:2603. 12977v3 Announce Type: replace Abstract: Foundation models are commonly deployed as frozen feature extractors with a small trainable head to adapt to private, user-generated data in federated settings.

arXiv Machine Learning
Sep 7

Client-Side Probing of Deleted Ridge Statistics in Federated Unlearning

The paper investigates how federated unlearning systems that broadcast updated linear classifiers after each client update can inadvertently leak the compact, additive summaries used for deletion. By submitting known changes and analyzing the returned classifiers, an attacker can recover the deleted sample’s class or even reinstate it. Experiments on MNIST and CIFAR‑10 show that high‑precision broadcasts enable exact label recovery, while lower precision limits fine‑grained recovery and diverse responses can prevent identification.

By Yijun Quan, Giovanni Montana
arXiv AI
Jun 2

How Hard Can It Be? Hardness-Aware Multi-Objective Unlearning

arXiv:2606. 02119v1 Announce Type: cross Abstract: Machine unlearning aims to remove the influence of specific forget training data due to privacy, copyright or bias concerns while maintaining the model performance on the remaining retain data.

By Jiangwei Chen, Xinyuan Niu, Rachael Hwee Ling Sim, Zhengyuan Liu, Nancy F. Chen, Bryan Kian Hsiang Low
arXiv AI
Sep 11

Forgetting Only What Matters: Layer-Selective Unlearning toward Robust LLMs

The paper introduces Forgetting Only What Matters via Unlearning Layers (FOM-UL), a layer‑selective unlearning framework for large language models. FOM-UL uses a forget‑to‑retain significance score to identify transformer layers that strongly influence the forget set while being insensitive to the retain set, allowing targeted updates that preserve most of the model. Experiments on TOFU, KnowUnDo, and MUSE-style benchmarks show that FOM-UL reduces residual memorization and maintains utility better than several baselines, even after 8‑bit and 4‑bit post‑training quantization, and it also limits recovery of forgotten content in adversarial prompt tests.

By Ravi Ranjan, Olivera Kotevska, Agoritsa Polyzou
arXiv AI
Jun 3

PURGE: Projected Unlearning via Retain-Guided Erasure

arXiv:2606. 03808v1 Announce Type: cross Abstract: We propose PURGE, a machine unlearning algorithm built on a simple but an under-exploited observation: continual learning (CL) and machine unlearning (MU) which are fundamentally dual problems.

By Vedant Jawandhia, Daksh Ahuja, Ghufran Alam Siddiqui, Prashant Trivedi, Yash Sinha, Pratik Narang