Backdoor Attacks and Defenses on Semantic-Symbol Reconstruction in Semantic Communications
Yuan Zhou, Rose Qingyang Hu, Yi Qian
TL;DR
This work addresses backdoor threats in semantic communications by introducing BASS, a paradigm that corrupts the semantics of reconstructed symbols in high-dimensional outputs. It proposes three defenses: a data-location based training framework to prevent poisoning, reverse-engineering methods to estimate backdoor triggers, and a post-training pruning approach that removes backdoor-related neurons while preserving reconstruction quality. Through MNIST and CIFAR-10 experiments, the authors show that BASS can be effectively triggered during inference yet mitigated by pruning at a knee point, with only modest degradation on clean data. The findings advance the security of semantic communications by enabling attack-aware defense strategies that do not rely solely on retraining with clean data.
Abstract
Semantic communication is of crucial importance for the next-generation wireless communication networks. The existing works have developed semantic communication frameworks based on deep learning. However, systems powered by deep learning are vulnerable to threats such as backdoor attacks and adversarial attacks. This paper delves into backdoor attacks targeting deep learning-enabled semantic communication systems. Since current works on backdoor attacks are not tailored for semantic communication scenarios, a new backdoor attack paradigm on semantic symbols (BASS) is introduced, based on which the corresponding defense measures are designed. Specifically, a training framework is proposed to prevent BASS. Additionally, reverse engineering-based and pruning-based defense strategies are designed to protect against backdoor attacks in semantic communication. Simulation results demonstrate the effectiveness of both the proposed attack paradigm and the defense strategies.
