Griffin: Towards Mixed Multi-Key Homomorphic Encryption

Thomas Schneider, Hossein Yalame, Michael Yonli

2023

Abstract

This paper presents Griffin, an extension of the mixed-scheme single-key homomorphic encryption framework Pegasus (Lu et al., IEEE S&P’21) to a Multi-Key Homomorphic Encryption (MKHE) scheme with applications to secure computation. MKHE is a generalized notion of Homomorphic Encryption (HE) that allows for operations on ciphertexts encrypted under different keys. However, an efficient approach to evaluate both polynomial and non-polynomial functions on encrypted data in MKHE has not yet been developed, hindering the deployment of HE to real-life applications. Griffin addresses this challenge by introducing a method for transforming between MKHE ciphertexts of different schemes. The practicality of Griffin is demonstrated through benchmarks with multiple applications, including the sorting of sixty four 45-bit fixed point numbers with a precision of 7 bits in 21 minutes, and evaluating arbitrary functions with a one-time setup communication of 1.4 GB per party and 2.34 MB per ciphertext. Moreover, Griffin could compute the maximum of two numbers in 3.2 seconds, a 2× improvement over existing MKHE approaches that rely on a single scheme.

Paper Citation

in Harvard Style

Schneider T., Yalame H. and Yonli M. (2023). Griffin: Towards Mixed Multi-Key Homomorphic Encryption. In Proceedings of the 20th International Conference on Security and Cryptography - Volume 1: SECRYPT; ISBN 978-989-758-666-8, SciTePress, pages 147-158. DOI: 10.5220/0012090200003555

in Bibtex Style

@conference{secrypt23,
author={Thomas Schneider and Hossein Yalame and Michael Yonli},
title={Griffin: Towards Mixed Multi-Key Homomorphic Encryption},
booktitle={Proceedings of the 20th International Conference on Security and Cryptography - Volume 1: SECRYPT},
year={2023},
pages={147-158},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0012090200003555},
isbn={978-989-758-666-8},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 20th International Conference on Security and Cryptography - Volume 1: SECRYPT
TI - Griffin: Towards Mixed Multi-Key Homomorphic Encryption
SN - 978-989-758-666-8
AU - Schneider T.
AU - Yalame H.
AU - Yonli M.
PY - 2023
SP - 147
EP - 158
DO - 10.5220/0012090200003555
PB - SciTePress