Generalizable Audio Deepfake Detection via Risk-Aware Style Alignment and Structural Empirical Risk Minimization

With the rapid advancement of AIGC technologies, audio deepfakes have become increasingly realistic, posing serious threats to information security and biometric authentication. Therefore, audio deepfake detection (ADD) has emerged as a critical and fast-evolving research area, particularly requiring superior generalization in out-of-domain scenarios. However, existing ADD methods suffer from constrained generalization and limited access to target data. To address these challenges, we propose Risk-Aware Style Alignment (RASA), a novel generalizable ADD framework that projects the style of any input feature into a shared style space through similarity-based projection. This alignment reduces both inter-domain and intra-source discrepancies without requiring target data during training. In addition, we adopt Structural Empirical Risk Minimization (SERM) in the Poincaré ball model to capture the hierarchical structure of the data and further minimize source risk. By jointly optimizing RASA and SERM, the proposed method effectively tightens the theoretical upper bound of target risk across three key dimensions: source risk, inter-domain divergence, and intra-source discrepancy. Extensive experiments demonstrate that our approach achieves superior generalization and outperforms existing state-of-the-art methods.