α-SAV: Generalized Weighted Input Verification for Secure Aggregation in Federated Learning

Abstract

Federated learning has found extensive application in the multimedia domain. However, due to its distributed nature, it is vulnerable to attacks such as Byzantine poisoning. To counteract malicious attacks, the secure aggregation process in federated learning requires input validation from participants. Existing input verification schemes, such as ACORN (USENIX Security 2023), ROFL (S&P 2023), et al., efficiently assess the validity of client inputs, but they fail to account for the impact of weights and do not support weighted secure aggregation. To address these issues, we propose α-SAV, an efficient weighted input verification scheme that utilizes Pedersen commitments to encrypt both privacy and weighted gradients. Our scheme incorporates a non-interactive zero-knowledge proof, the Sigma protocol, allowing clients to generate input proofs without interacting with the server. Verified inputs can then contribute to weighted aggregation. α-SAV is highly compatible, seamlessly integrating into existing federated learning frameworks with minimal additional cost. Experimental results demonstrate that the cost of α-SAV is linear. When trained on the MNIST dataset, the client computation time for α-SAV is 1.6 seconds, resulting in only 24% additional cost compared to ACORN and 3% compared to ROFL.