Secure Aggregation in Federated Learning using Multiparty Homomorphic Encryption

Fuente: arXiv
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Main Authors: Hosseini, Erfan, Chen, Shuangyi, Khisti, Ashish
Format: Preprint
Published: 2025
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author Hosseini, Erfan
Chen, Shuangyi
Khisti, Ashish
author_facet Hosseini, Erfan
Chen, Shuangyi
Khisti, Ashish
contents A key operation in federated learning is the aggregation of gradient vectors generated by individual client nodes. We develop a method based on multiparty homomorphic encryption (MPHE) that enables the central node to compute this aggregate, while receiving only encrypted version of each individual gradients. Towards this end, we extend classical MPHE methods so that the decryption of the aggregate vector can be successful even when only a subset of client nodes are available. This is accomplished by introducing a secret-sharing step during the setup phase of MPHE when the public encryption key is generated. We develop conditions on the parameters of the MPHE scheme that guarantee correctness of decryption and (computational) security. We explain how our method can be extended to accommodate client nodes that do not participate during the setup phase. We also propose a compression scheme for gradient vectors at each client node that can be readily combined with our MPHE scheme and perform the associated convergence analysis. We discuss the advantages of our proposed scheme with other approaches based on secure multi-party computation. Finally we discuss a practical implementation of our system, compare the performance of our system with different approaches, and demonstrate that by suitably combining compression with encryption the overhead over baseline schemes is rather small.
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id arxiv_https___arxiv_org_abs_2503_00581
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Secure Aggregation in Federated Learning using Multiparty Homomorphic Encryption
Hosseini, Erfan
Chen, Shuangyi
Khisti, Ashish
Cryptography and Security
A key operation in federated learning is the aggregation of gradient vectors generated by individual client nodes. We develop a method based on multiparty homomorphic encryption (MPHE) that enables the central node to compute this aggregate, while receiving only encrypted version of each individual gradients. Towards this end, we extend classical MPHE methods so that the decryption of the aggregate vector can be successful even when only a subset of client nodes are available. This is accomplished by introducing a secret-sharing step during the setup phase of MPHE when the public encryption key is generated. We develop conditions on the parameters of the MPHE scheme that guarantee correctness of decryption and (computational) security. We explain how our method can be extended to accommodate client nodes that do not participate during the setup phase. We also propose a compression scheme for gradient vectors at each client node that can be readily combined with our MPHE scheme and perform the associated convergence analysis. We discuss the advantages of our proposed scheme with other approaches based on secure multi-party computation. Finally we discuss a practical implementation of our system, compare the performance of our system with different approaches, and demonstrate that by suitably combining compression with encryption the overhead over baseline schemes is rather small.
title Secure Aggregation in Federated Learning using Multiparty Homomorphic Encryption
topic Cryptography and Security
url https://arxiv.org/abs/2503.00581