An Efficient Signature Scheme From Supersingular Elliptic Curve Isogenies

Since supersingular elliptic curve isogenies are one of the several candidate sources of hardness for building post-quantum cryptographic primitives, the research of efficient signature schemes based on them is still a hot topic. In this paper, we present a many-time signature scheme based on the hash function from supersingular elliptic curve isogenies over the finite field <inline-formula> <tex-math notation="LaTeX">$\mathbb {F}_{p^{2}}$ </tex-math></inline-formula> where <inline-formula> <tex-math notation="LaTeX">$p=2^{521}-1$ </tex-math></inline-formula>. Our signature scheme achieves smaller signature sizes relative to other post-quantum signature schemes based on supersingular elliptic curve isogenies, such as Galbraith’s signature schemes (AsiaCrypt 2017) and Yoo’s scheme (FC 2017). The structure of our scheme follows that of the hash-based signature scheme submitted to National Institute of Standards and Technology for post-quantum cryptography in 2018 with some modifications. To complete the construction, we firstly apply the method of Weil restriction to improve the efficiency of hash function from supersingular elliptic curve isogenies by approximately 30%, then propose a new Winternitz one-time signature scheme based on the hash function. Finally, we implement the signature scheme.