Efficient Decentralized Federated Singular Vector Decomposition

Federated singular value decomposition (SVD) is a foundation for many real-world distributed applications. Existing federated SVD studies either require external servers which downgrade privacy protection or leverage homomorphic encryption (HE) to get rid of external servers (i.e., being decentralized) but suffer from significant inefficiencies caused by extensive computational and communication overhead.

This paper presents Excalibur 1 , an efficient decentralized federated SVD system. At its core, Excalibur proposes a lightweight matrix protection method to reduce the computational degradation caused by cryptographic operations, improving computation performance. Furthermore, it designs a communication-efficient decentralized SVD workflow based on the quantitative analysis of the design space, optimizing communication performance. To validate the efficiency of Excalibur, we implement a fully functional Excalibur system and evaluate it with real-world applications. Our results show that Excalibur not only removes the external servers but also achieves 3.1× ∼ 6.0× faster performance than state-ofthe-art (SOTA) server-aided method on different shapes of billion-scale data. In addition, Excalibur exhibits > 23000× larger throughput than the SOTA HE-based system.