Deep neural networks are vulnerable to backdoor attacks, but existing defenses require labeled data to purify compromised models, limiting their application beyond supervised learning settings.
A new defense technique called Two-stage Symmetry Connectivity (TSC) has been proposed to address backdoor attacks independently of data format and with only a small fraction of clean samples required.
TSC leverages permutation invariance and quadratic mode connectivity in neural networks to increase the loss on poisoned samples while maintaining bounded clean accuracy.
Experiments show that TSC achieves robust performance comparable to state-of-the-art methods in supervised learning and can also generalize to self-supervised learning frameworks like SimCLR and CLIP.