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Main Authors: Shi, Yuhui, Yang, Yehan, Sheng, Qiang, Mi, Hao, Hu, Beizhe, Xu, Chaoxi, Cao, Juan
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2506.15683
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author Shi, Yuhui
Yang, Yehan
Sheng, Qiang
Mi, Hao
Hu, Beizhe
Xu, Chaoxi
Cao, Juan
author_facet Shi, Yuhui
Yang, Yehan
Sheng, Qiang
Mi, Hao
Hu, Beizhe
Xu, Chaoxi
Cao, Juan
contents With the popularity of large language models (LLMs), undesirable societal problems like misinformation production and academic misconduct have been more severe, making LLM-generated text detection now of unprecedented importance. Although existing methods have made remarkable progress, a new challenge posed by text from privately tuned LLMs remains underexplored. Users could easily possess private LLMs by fine-tuning an open-source one with private corpora, resulting in a significant performance drop of existing detectors in practice. To address this issue, we propose PhantomHunter, an LLM-generated text detector specialized for detecting text from unseen, privately-tuned LLMs. Its family-aware learning framework captures family-level traits shared across the base models and their derivatives, instead of memorizing individual characteristics. Experiments on data from LLaMA, Gemma, and Mistral families show its superiority over 7 baselines and 3 industrial services, with F1 scores of over 96%.
format Preprint
id arxiv_https___arxiv_org_abs_2506_15683
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PhantomHunter: Detecting Unseen Privately-Tuned LLM-Generated Text via Family-Aware Learning
Shi, Yuhui
Yang, Yehan
Sheng, Qiang
Mi, Hao
Hu, Beizhe
Xu, Chaoxi
Cao, Juan
Computation and Language
Computers and Society
With the popularity of large language models (LLMs), undesirable societal problems like misinformation production and academic misconduct have been more severe, making LLM-generated text detection now of unprecedented importance. Although existing methods have made remarkable progress, a new challenge posed by text from privately tuned LLMs remains underexplored. Users could easily possess private LLMs by fine-tuning an open-source one with private corpora, resulting in a significant performance drop of existing detectors in practice. To address this issue, we propose PhantomHunter, an LLM-generated text detector specialized for detecting text from unseen, privately-tuned LLMs. Its family-aware learning framework captures family-level traits shared across the base models and their derivatives, instead of memorizing individual characteristics. Experiments on data from LLaMA, Gemma, and Mistral families show its superiority over 7 baselines and 3 industrial services, with F1 scores of over 96%.
title PhantomHunter: Detecting Unseen Privately-Tuned LLM-Generated Text via Family-Aware Learning
topic Computation and Language
Computers and Society
url https://arxiv.org/abs/2506.15683