Necessary and Sufficient Watermark for Large Language Models

Fuente: arXiv
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Hauptverfasser: Takezawa, Yuki, Sato, Ryoma, Bao, Han, Niwa, Kenta, Yamada, Makoto
Format: Preprint
Veröffentlicht: 2023
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author Takezawa, Yuki
Sato, Ryoma
Bao, Han
Niwa, Kenta
Yamada, Makoto
author_facet Takezawa, Yuki
Sato, Ryoma
Bao, Han
Niwa, Kenta
Yamada, Makoto
contents In recent years, large language models (LLMs) have achieved remarkable performances in various NLP tasks. They can generate texts that are indistinguishable from those written by humans. Such remarkable performance of LLMs increases their risk of being used for malicious purposes, such as generating fake news articles. Therefore, it is necessary to develop methods for distinguishing texts written by LLMs from those written by humans. Watermarking is one of the most powerful methods for achieving this. Although existing watermarking methods have successfully detected texts generated by LLMs, they significantly degrade the quality of the generated texts. In this study, we propose the Necessary and Sufficient Watermark (NS-Watermark) for inserting watermarks into generated texts without degrading the text quality. More specifically, we derive minimum constraints required to be imposed on the generated texts to distinguish whether LLMs or humans write the texts. Then, we formulate the NS-Watermark as a constrained optimization problem and propose an efficient algorithm to solve it. Through the experiments, we demonstrate that the NS-Watermark can generate more natural texts than existing watermarking methods and distinguish more accurately between texts written by LLMs and those written by humans. Especially in machine translation tasks, the NS-Watermark can outperform the existing watermarking method by up to 30 BLEU scores.
format Preprint
id arxiv_https___arxiv_org_abs_2310_00833
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Necessary and Sufficient Watermark for Large Language Models
Takezawa, Yuki
Sato, Ryoma
Bao, Han
Niwa, Kenta
Yamada, Makoto
Computation and Language
Machine Learning
In recent years, large language models (LLMs) have achieved remarkable performances in various NLP tasks. They can generate texts that are indistinguishable from those written by humans. Such remarkable performance of LLMs increases their risk of being used for malicious purposes, such as generating fake news articles. Therefore, it is necessary to develop methods for distinguishing texts written by LLMs from those written by humans. Watermarking is one of the most powerful methods for achieving this. Although existing watermarking methods have successfully detected texts generated by LLMs, they significantly degrade the quality of the generated texts. In this study, we propose the Necessary and Sufficient Watermark (NS-Watermark) for inserting watermarks into generated texts without degrading the text quality. More specifically, we derive minimum constraints required to be imposed on the generated texts to distinguish whether LLMs or humans write the texts. Then, we formulate the NS-Watermark as a constrained optimization problem and propose an efficient algorithm to solve it. Through the experiments, we demonstrate that the NS-Watermark can generate more natural texts than existing watermarking methods and distinguish more accurately between texts written by LLMs and those written by humans. Especially in machine translation tasks, the NS-Watermark can outperform the existing watermarking method by up to 30 BLEU scores.
title Necessary and Sufficient Watermark for Large Language Models
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2310.00833