MotiGAN: Game Theory Meets the Motivated Intruder Test for Re-identification Risk Generation and Annotation in Pseudonymisation

Xuan-Son Vu, Tien Dat Dang, Elena Volodina


Abstract
Re-identification methods serve as a concrete instantiation of the Motivated Intruder Test in privacy-preserving problems, and current state-of-the-art attack techniques are predominantly built upon Large Language Models (LLMs) which are also core components of robust pseudonymized methods. Therefore, it requires the rich training dataset. However, as research demands continue to grow while publicly available data for each domain remains limited and the cost of direct human supervision is high, a central question arises: how can a human-in-the-loop approach be integrated to generate high-quality data and improve the performance of LLMs in psedonymization. To address this limitation, we propose MOTIGAN1 - a gamified framework that transforms the motivated intruder test into a competitive three population tournament. In this game, human characters and AI characters compete to re-identify individuals from each essay. At every stage, players both commit their guesses and contribute to enriching the synthesized dataset. In our experiments, the synthesized dataset contributes to improving the performance of multiple models in several experiments (achieving up to 37.6% improvement on a well-established benchmark).
Anthology ID:
2026.emnlp-industry.256
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
4328–4337
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.256/
DOI:
Bibkey:
Cite (ACL):
Xuan-Son Vu, Tien Dat Dang, and Elena Volodina. 2026. MotiGAN: Game Theory Meets the Motivated Intruder Test for Re-identification Risk Generation and Annotation in Pseudonymisation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 4328–4337, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MotiGAN: Game Theory Meets the Motivated Intruder Test for Re-identification Risk Generation and Annotation in Pseudonymisation (Vu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.256.pdf