Faster optimal ate pairings for cyclotomic sparse families of pairing-friendly elliptic curves with embedding degrees k = 5,7

Abstract

Nowadays, pairing-based cryptography researchers are looking for new parameters for standard security levels against the new number field sieve tower number field sieve algorithm. Recently, they have suggested new parameters for well-studied pairing-friendly curves with odd embedding degrees five and seven resistant to this attack. In this paper, we define optimal ate pairing on curves using sparse families with embedding degrees five and seven. We also provide details to perform the miller loop and the final exponentiation using addition chain process. Our theoretical results costs indicate that these families of curves offer the best performance in the computation of the optimal ate pairing at the 128-bit security level compared to Cocks–Pinch curves of embedding degrees five and seven. The improvement is about [Formula: see text] and [Formula: see text] faster than the optimal ate pairing previously computed on Cocks–Pinch curves of embedding degrees five and seven, respectively.