ONION: A Simple and Effective Defense Against Textual Backdoor Attacks Fanchao Qi author Yangyi Chen author Mukai Li author Yuan Yao author Zhiyuan Liu author Maosong Sun author 2021-11 text Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing Marie-Francine Moens editor Xuanjing Huang editor Lucia Specia editor Scott Wen-tau Yih editor Association for Computational Linguistics Online and Punta Cana, Dominican Republic conference publication qi-etal-2021-onion 10.18653/v1/2021.emnlp-main.752 https://aclanthology.org/2021.emnlp-main.752/ 2021-11 9558 9566