  Text watermarking algorithms are crucial for protecting the copyright of
textual content. Historically, their capabilities and application scenarios
were limited. However, recent advancements in large language models (LLMs) have
revolutionized these techniques. LLMs not only enhance text watermarking
algorithms with their advanced abilities but also create a need for employing
these algorithms to protect their own copyrights or prevent potential misuse.
This paper conducts a comprehensive survey of the current state of text
watermarking technology, covering four main aspects: (1) an overview and
comparison of different text watermarking techniques; (2) evaluation methods
for text watermarking algorithms, including their detectability, impact on text
or LLM quality, robustness under target or untargeted attacks; (3) potential
application scenarios for text watermarking technology; (4) current challenges
and future directions for text watermarking. This survey aims to provide
researchers with a thorough understanding of text watermarking technology in
the era of LLM, thereby promoting its further advancement.
