Segmenting Watermarked Texts From Language Models

Fuente: arXiv
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Main Authors: Li, Xingchi, Li, Guanxun, Zhang, Xianyang
Format: Preprint
Published: 2024
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author Li, Xingchi
Li, Guanxun
Zhang, Xianyang
author_facet Li, Xingchi
Li, Guanxun
Zhang, Xianyang
contents Watermarking is a technique that involves embedding nearly unnoticeable statistical signals within generated content to help trace its source. This work focuses on a scenario where an untrusted third-party user sends prompts to a trusted language model (LLM) provider, who then generates a text from their LLM with a watermark. This setup makes it possible for a detector to later identify the source of the text if the user publishes it. The user can modify the generated text by substitutions, insertions, or deletions. Our objective is to develop a statistical method to detect if a published text is LLM-generated from the perspective of a detector. We further propose a methodology to segment the published text into watermarked and non-watermarked sub-strings. The proposed approach is built upon randomization tests and change point detection techniques. We demonstrate that our method ensures Type I and Type II error control and can accurately identify watermarked sub-strings by finding the corresponding change point locations. To validate our technique, we apply it to texts generated by several language models with prompts extracted from Google's C4 dataset and obtain encouraging numerical results. We release all code publicly at https://github.com/doccstat/llm-watermark-cpd.
format Preprint
id arxiv_https___arxiv_org_abs_2410_20670
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Segmenting Watermarked Texts From Language Models
Li, Xingchi
Li, Guanxun
Zhang, Xianyang
Machine Learning
Multimedia
Neural and Evolutionary Computing
Watermarking is a technique that involves embedding nearly unnoticeable statistical signals within generated content to help trace its source. This work focuses on a scenario where an untrusted third-party user sends prompts to a trusted language model (LLM) provider, who then generates a text from their LLM with a watermark. This setup makes it possible for a detector to later identify the source of the text if the user publishes it. The user can modify the generated text by substitutions, insertions, or deletions. Our objective is to develop a statistical method to detect if a published text is LLM-generated from the perspective of a detector. We further propose a methodology to segment the published text into watermarked and non-watermarked sub-strings. The proposed approach is built upon randomization tests and change point detection techniques. We demonstrate that our method ensures Type I and Type II error control and can accurately identify watermarked sub-strings by finding the corresponding change point locations. To validate our technique, we apply it to texts generated by several language models with prompts extracted from Google's C4 dataset and obtain encouraging numerical results. We release all code publicly at https://github.com/doccstat/llm-watermark-cpd.
title Segmenting Watermarked Texts From Language Models
topic Machine Learning
Multimedia
Neural and Evolutionary Computing
url https://arxiv.org/abs/2410.20670