Exposing LLM User Privacy via Traffic Fingerprint Analysis: A Study of Privacy Risks in LLM Agent Interactions

Fuente: arXiv
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Hauptverfasser: Zhang, Yixiang, Deng, Xinhao, Gu, Zhongyi, Chen, Yihao, Xu, Ke, Li, Qi, Wu, Jianping
Format: Preprint
Veröffentlicht: 2025
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author Zhang, Yixiang
Deng, Xinhao
Gu, Zhongyi
Chen, Yihao
Xu, Ke
Li, Qi
Wu, Jianping
author_facet Zhang, Yixiang
Deng, Xinhao
Gu, Zhongyi
Chen, Yihao
Xu, Ke
Li, Qi
Wu, Jianping
contents Large Language Models (LLMs) are increasingly deployed as agents that orchestrate tasks and integrate external tools to execute complex workflows. We demonstrate that these interactive behaviors leave distinctive fingerprints in encrypted traffic exchanged between users and LLM agents. By analyzing traffic patterns associated with agent workflows and tool invocations, adversaries can infer agent activities, distinguish specific agents, and even profile sensitive user attributes. To highlight this risk, we develop AgentPrint, which achieves an F1-score of 0.866 in agent identification and attains 73.9% and 69.1% top-3 accuracy in user attribute inference for simulated- and real-user settings, respectively. These results uncover an overlooked risk: the very interactivity that empowers LLM agents also exposes user privacy, underscoring the urgent need for technical countermeasures alongside regulatory and policy safeguards.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07176
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exposing LLM User Privacy via Traffic Fingerprint Analysis: A Study of Privacy Risks in LLM Agent Interactions
Zhang, Yixiang
Deng, Xinhao
Gu, Zhongyi
Chen, Yihao
Xu, Ke
Li, Qi
Wu, Jianping
Cryptography and Security
Large Language Models (LLMs) are increasingly deployed as agents that orchestrate tasks and integrate external tools to execute complex workflows. We demonstrate that these interactive behaviors leave distinctive fingerprints in encrypted traffic exchanged between users and LLM agents. By analyzing traffic patterns associated with agent workflows and tool invocations, adversaries can infer agent activities, distinguish specific agents, and even profile sensitive user attributes. To highlight this risk, we develop AgentPrint, which achieves an F1-score of 0.866 in agent identification and attains 73.9% and 69.1% top-3 accuracy in user attribute inference for simulated- and real-user settings, respectively. These results uncover an overlooked risk: the very interactivity that empowers LLM agents also exposes user privacy, underscoring the urgent need for technical countermeasures alongside regulatory and policy safeguards.
title Exposing LLM User Privacy via Traffic Fingerprint Analysis: A Study of Privacy Risks in LLM Agent Interactions
topic Cryptography and Security
url https://arxiv.org/abs/2510.07176