Semantic Self-Guided Watermarking with Enhanced Text Quality for Large Language Models

Linkang Yang, Bo Zhang, Bin Mao, Jiajun Cheng, Junbo Fu, Bingxu Han, Bo Han, Jun Zhang, Guoshuai Zhao, Zhunchen Luo, Yunbo Cao, Xiaoying Bai, Guotong Geng


Abstract
The rapid development of large language models (LLMs) has created an urgent need for identifying machine-generated texts, and text watermarking technology has proven to be an effective solution. However, current watermarking methods, while demonstrating strong detectability, significantly degrade text quality due to the introduction of unnatural tokens. The main reason lies in the fact that these methods ignore the importance of semantic information in the watermarking process. To address this issue, we note that the logit vector produced by LLMs encodes both semantic understanding of input texts and prediction confidence across different tokens. Therefore, we propose a novel Semantic Self-Guided Watermarking (SSGW) framework that leverages the LLM itself to generate a guidance logic vector that assists in watermarking while producing the original one concurrently. Subsequently, we design a transform module to analyze these two vectors comprehensively and then transform them into adaptive watermark logits for different candidate tokens, thereby reducing the possibility of selecting inappropriate tokens. Experimental results confirm the effectiveness of our method in achieving superior performance in both watermark detectability and text quality preservation. The source code will be made publicly available upon acceptance.
Anthology ID:
2026.emnlp-main.252
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
5740–5751
Language:
URL:
https://aclanthology.org/2026.emnlp-main.252/
DOI:
Bibkey:
Cite (ACL):
Linkang Yang, Bo Zhang, Bin Mao, Jiajun Cheng, Junbo Fu, Bingxu Han, Bo Han, Jun Zhang, Guoshuai Zhao, Zhunchen Luo, Yunbo Cao, Xiaoying Bai, and Guotong Geng. 2026. Semantic Self-Guided Watermarking with Enhanced Text Quality for Large Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 5740–5751, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Semantic Self-Guided Watermarking with Enhanced Text Quality for Large Language Models (Yang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.252.pdf