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Main Authors: Wang, Yujing, Zhang, Hainan, Pang, Liang, Tong, Yongxin, Guo, Binghui, Zheng, Hongwei, Zheng, Zhiming
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.09910
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author Wang, Yujing
Zhang, Hainan
Pang, Liang
Tong, Yongxin
Guo, Binghui
Zheng, Hongwei
Zheng, Zhiming
author_facet Wang, Yujing
Zhang, Hainan
Pang, Liang
Tong, Yongxin
Guo, Binghui
Zheng, Hongwei
Zheng, Zhiming
contents Retrieval-Augmented Generation (RAG) is a promising technique for applying LLMs to proprietary domains. However, retrieved documents may contain sensitive knowledge, posing risks of privacy leakage in generative results. Thus, effectively erasing private information from retrieved documents is a key challenge for RAG. Unlike traditional text anonymization, RAG should consider: (1) the inherent multi-document reasoning may face de-anonymization attacks; (2) private knowledge varies by scenarios, so users should be allowed to customize which information to erase; (3) preserving sufficient publicly available knowledge for generation tasks. This paper introduces the privacy erasure task for RAG and proposes Eraser4RAG, a private knowledge eraser which effectively removes user-defined private knowledge from documents while preserving sufficient public knowledge for generation. Specifically, we first construct a global knowledge graph to identify potential knowledge across documents, aiming to defend against de-anonymization attacks. Then we randomly split it into private and public sub-graphs, and fine-tune Flan-T5 to rewrite the retrieved documents excluding private triples. Finally, PPO algorithm optimizes the rewriting model to minimize private triples and maximize public triples retention. Experiments on four QA datasets demonstrate that Eraser4RAG achieves superior erase performance than GPT-4o.
format Preprint
id arxiv_https___arxiv_org_abs_2504_09910
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning to Erase Private Knowledge from Multi-Documents for Retrieval-Augmented Large Language Models
Wang, Yujing
Zhang, Hainan
Pang, Liang
Tong, Yongxin
Guo, Binghui
Zheng, Hongwei
Zheng, Zhiming
Computation and Language
Retrieval-Augmented Generation (RAG) is a promising technique for applying LLMs to proprietary domains. However, retrieved documents may contain sensitive knowledge, posing risks of privacy leakage in generative results. Thus, effectively erasing private information from retrieved documents is a key challenge for RAG. Unlike traditional text anonymization, RAG should consider: (1) the inherent multi-document reasoning may face de-anonymization attacks; (2) private knowledge varies by scenarios, so users should be allowed to customize which information to erase; (3) preserving sufficient publicly available knowledge for generation tasks. This paper introduces the privacy erasure task for RAG and proposes Eraser4RAG, a private knowledge eraser which effectively removes user-defined private knowledge from documents while preserving sufficient public knowledge for generation. Specifically, we first construct a global knowledge graph to identify potential knowledge across documents, aiming to defend against de-anonymization attacks. Then we randomly split it into private and public sub-graphs, and fine-tune Flan-T5 to rewrite the retrieved documents excluding private triples. Finally, PPO algorithm optimizes the rewriting model to minimize private triples and maximize public triples retention. Experiments on four QA datasets demonstrate that Eraser4RAG achieves superior erase performance than GPT-4o.
title Learning to Erase Private Knowledge from Multi-Documents for Retrieval-Augmented Large Language Models
topic Computation and Language
url https://arxiv.org/abs/2504.09910