CryptoDB
QFESTA: Efficient Algorithms and Parameters for FESTA using Quaternion Algebras
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| Conference: | CRYPTO 2024 |
| Abstract: | In 2023, Basso, Maino, and Pope proposed FESTA~(Fast Encryption from Supersingular Torsion Attacks), an isogeny-based public-key encryption (PKE) protocol that uses the SIDH attack for decryption. In the same paper, they proposed parameters for that protocol, but the parameters require high-degree isogeny computations. In this paper, we introduce QFESTA~(Quaternion Fast Encapsulation from Supersingular Torsion Attacks), a new variant of FESTA that works with better parameters using quaternion algebras and achieves IND-CCA security under QROM. To realize our protocol, we construct a new algorithm to compute an isogeny of non-smooth degree using quaternion algebras and the SIDH attack. Our protocol relies solely on $(2,2)$-isogeny and $3$-isogeny computations, promising a substantial reduction in computational costs. In addition, our protocol has significantly smaller data sizes for public keys and ciphertexts, approximately half size of the original FESTA. |
BibTeX
@inproceedings{crypto-2024-34179,
title={QFESTA: Efficient Algorithms and Parameters for FESTA using Quaternion Algebras},
publisher={Springer-Verlag},
author={Kohei Nakagawa and Hiroshi Onuki},
year=2024
}