Why TaylorMLP Fails? Revisiting LLM Weight Protection Schemes with Adversarial Games

Bintao Tang, Xin Yang, Letian Li, Yu Meng, Kwok Wai Lui, Yuhao Wang, Zimo Ji, Terry Jingchen Zhang, Wenyuan Jiang


Abstract
Open-weight large language models create demand for weight protection schemes that let users run models locally while preserving developer control over valuable model weights. Existing schemes, however, are often justified by heuristic arguments and empirical checks rather than explicit adversarial goals, security definitions, or proofs. As a case study, we analyze a recent scheme previously published in *EMNLP 2024 Main Conference* and show that it is vulnerable to our efficient weight-extraction attack, recovering more than 99.95% of protected parameters and producing reconstructed models with near-identical performance. Motivated by this failure, we formulate LLM weight protection schemes through game-based definitions, and we discuss how these notions relate. We encourage that future weight protection schemes should be designed with formal security goals, proof-oriented analysis, and offensive evaluation rather than relying on informal intuition alone.
Anthology ID:
2026.findings-emnlp.1378
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
29296–29310
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1378/
DOI:
Bibkey:
Cite (ACL):
Bintao Tang, Xin Yang, Letian Li, Yu Meng, Kwok Wai Lui, Yuhao Wang, Zimo Ji, Terry Jingchen Zhang, and Wenyuan Jiang. 2026. Why TaylorMLP Fails? Revisiting LLM Weight Protection Schemes with Adversarial Games. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 29296–29310, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Why TaylorMLP Fails? Revisiting LLM Weight Protection Schemes with Adversarial Games (Tang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1378.pdf