The complexity of elliptic normal bases
Daniel Panario, Mohamadou Sall, Qiang Wang
TL;DR
This work addresses the complexity of elliptic normal bases arising from elliptic-period constructions, focusing on the weight of the multiplication tensor and its dependence on elliptic-curve data. It introduces a precise framework tying $C({\mathcal N})$ to vector weights derived from two points on an elliptic curve and proves upper and lower bounds that depend on these weights. The study finds that many contributing vectors tend to be dense, complicating efforts to achieve low-complexity bases, and demonstrates how the curve choice can markedly affect actual complexity through concrete Magma-based examples. The results guide future research toward selecting elliptic-curve data that yield low-weight special vectors to realize more efficient elliptic normal bases in practice.
Abstract
We study the complexity (that is, the weight of the multiplication table) of the elliptic normal bases introduced by Couveignes and Lercier. We give an upper bound on the complexity of these elliptic normal bases, and we analyze the weight of some special vectors related to the multiplication table of those bases. This analysis leads us to some perspectives on the search for low complexity normal bases from elliptic periods.
