Abstract
Retrieval-Augmented Generation (RAG) has emerged as a powerful paradigm for improving the quality of generated contents of Large Language Models (LLMs) by grounding responses in external knowledge, thus reducing hallucinations and factual errors. However, recent studies have highlighted a critical vulnerability: adversaries can exploit the retrieval process to extract personally identifiable information (PII) from the underlying corpus. To mitigate this risk, we propose a novel defense, RAG-CT, that identifies malicious queries by analyzing their entropy and margin distributions and using a score-based detection method. Extensive experiments with four state-of-the-art attack strategies and four defense baselines on two datasets show that our approach significantly reduces PII leakage while outperforming existing defenses. This work provides a lightweight yet effective mechanism to protect RAG systems against PII leakage without requiring modifications to the underlying LLM or retriever.
Keywords
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Publication details
- Journal
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- Open access
- Green open access
Cite this article
APA 7
Lyu, X., Wang, J., He, J., Wang, N., Hu, Y., & Chen, Y. (2026). RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution. https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution
MLA 9
Lyu, Xingyu, et al. "RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution." https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution.
Chicago (author–date)
Lyu, Xingyu, Jiayimei Wang, Jianfeng He, Ning Wang, Yidan Hu, and Yimin Chen. 2026. "RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution." https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution.
Harvard
Lyu, X., Wang, J., He, J., Wang, N., Hu, Y. and Chen, Y. (2026) 'RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution', Available at: https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution.
Vancouver
Lyu X, Wang J, He J, Wang N, Hu Y, Chen Y. RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution. https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution
IEEE
X. Lyu, J. Wang, J. He, N. Wang, Y. Hu, and Y. Chen, "RAG-CT: Mitigating Privacy Risks on Retrieval-Augmented Generation Systems via Scanning Prompt Distribution," https://omanscience.com/en/articles/rag-ct-mitigating-privacy-risks-on-retrieval-augmented-generation-systems-via-scanning-prompt-distribution.