EFMVFL: An Efficient and Flexible Multi-party Vertical Federated Learning without a Third Party

TL;DR

EFMVFL introduces a secure, efficient, and flexible multi-party vertical federated learning framework that eliminates the need for a third-party, supporting generalized linear models with low communication overhead.

Contribution

The paper proposes EFMVFL, a novel VFL framework combining secret sharing and homomorphic encryption, avoiding third-party reliance and enabling multi-party expansion.

Findings

Framework is secure and efficient

Supports multiple participants with low communication costs

Applicable to logistic and Poisson regression models

Abstract

Federated learning allows multiple participants to conduct joint modeling without disclosing their local data. Vertical federated learning (VFL) handles the situation where participants share the same ID space and different feature spaces. In most VFL frameworks, to protect the security and privacy of the participants' local data, a third party is needed to generate homomorphic encryption key pairs and perform decryption operations. In this way, the third party is granted the right to decrypt information related to model parameters. However, it isn't easy to find such a credible entity in the real world. Existing methods for solving this problem are either communication-intensive or unsuitable for multi-party scenarios. By combining secret sharing and homomorphic encryption, we propose a novel VFL framework without a third party called EFMVFL, which supports flexible expansion to multiple participants with low communication overhead and is applicable to generalized linear models. We give instantiations of our framework under logistic regression and Poisson regression. Theoretical analysis and experiments show that our framework is secure, more efficient, and easy to be extended to multiple participants.