Robust and Efficient Watermarking of Large Language Models Using Error Correction Codes

Large language models (LLMs) have demonstrated remarkable performance in various tasks, but they also face challenges in intellectual property (IP) protection. Traditional training-based watermarking techniques are computationally expensive, while function invariant transformations (FITs) offer a lightweight alternative. Nevertheless, FIT-based watermarking methods are vulnerable to adaptive attacks, where adversaries can exploit the same transformation to remove or forge watermarks. We propose a novel white-box watermarking scheme that combines error correction codes (ECCs) with weight permutations. By encoding model identifiers using ECCs, our approach guarantees reliable watermark extraction under various attacks. Additionally, we develop a linear assignment-based extraction algorithm to enhance its efficiency. Evaluations on six LLMs show that our method offers robust watermarking capabilities. It has a minimal impact on model performance while effectively defending against removal and forgery attacks. Overall, our approach provides a scalable and secure solution for safeguarding the copyrights of LLMs.