ForgetMark: Stealthy Fingerprint Embedding via Targeted Unlearning in Language Models

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Xu, Zhenhua, Zhang, Haobo, Wang, Zhebo, Liu, Qichen, Xu, Haitao, Xing, Wenpeng, Han, Meng
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866912833193639936
author Xu, Zhenhua
Zhang, Haobo
Wang, Zhebo
Liu, Qichen
Xu, Haitao
Xing, Wenpeng
Han, Meng
author_facet Xu, Zhenhua
Zhang, Haobo
Wang, Zhebo
Liu, Qichen
Xu, Haitao
Xing, Wenpeng
Han, Meng
contents Existing invasive (backdoor) fingerprints suffer from high-perplexity triggers that are easily filtered, fixed response patterns exposed by heuristic detectors, and spurious activations on benign inputs. We introduce \textsc{ForgetMark}, a stealthy fingerprinting framework that encodes provenance via targeted unlearning. It builds a compact, human-readable key--value set with an assistant model and predictive-entropy ranking, then trains lightweight LoRA adapters to suppress the original values on their keys while preserving general capabilities. Ownership is verified under black/gray-box access by aggregating likelihood and semantic evidence into a fingerprint success rate. By relying on probabilistic forgetting traces rather than fixed trigger--response patterns, \textsc{ForgetMark} avoids high-perplexity triggers, reduces detectability, and lowers false triggers. Across diverse architectures and settings, it achieves 100\% ownership verification on fingerprinted models while maintaining standard performance, surpasses backdoor baselines in stealthiness and robustness to model merging, and remains effective under moderate incremental fine-tuning. Our code and data are available at \href{https://github.com/Xuzhenhua55/ForgetMark}{https://github.com/Xuzhenhua55/ForgetMark}.
format Preprint
id arxiv_https___arxiv_org_abs_2601_08189
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ForgetMark: Stealthy Fingerprint Embedding via Targeted Unlearning in Language Models
Xu, Zhenhua
Zhang, Haobo
Wang, Zhebo
Liu, Qichen
Xu, Haitao
Xing, Wenpeng
Han, Meng
Cryptography and Security
Artificial Intelligence
Existing invasive (backdoor) fingerprints suffer from high-perplexity triggers that are easily filtered, fixed response patterns exposed by heuristic detectors, and spurious activations on benign inputs. We introduce \textsc{ForgetMark}, a stealthy fingerprinting framework that encodes provenance via targeted unlearning. It builds a compact, human-readable key--value set with an assistant model and predictive-entropy ranking, then trains lightweight LoRA adapters to suppress the original values on their keys while preserving general capabilities. Ownership is verified under black/gray-box access by aggregating likelihood and semantic evidence into a fingerprint success rate. By relying on probabilistic forgetting traces rather than fixed trigger--response patterns, \textsc{ForgetMark} avoids high-perplexity triggers, reduces detectability, and lowers false triggers. Across diverse architectures and settings, it achieves 100\% ownership verification on fingerprinted models while maintaining standard performance, surpasses backdoor baselines in stealthiness and robustness to model merging, and remains effective under moderate incremental fine-tuning. Our code and data are available at \href{https://github.com/Xuzhenhua55/ForgetMark}{https://github.com/Xuzhenhua55/ForgetMark}.
title ForgetMark: Stealthy Fingerprint Embedding via Targeted Unlearning in Language Models
topic Cryptography and Security
Artificial Intelligence
url https://arxiv.org/abs/2601.08189