scholarly journals Computing endomorphism rings of supersingular elliptic curves and connections to path-finding in isogeny graphs

2020 ◽  
Vol 4 (1) ◽  
pp. 215-232
Author(s):  
Kirsten Eisenträger ◽  
Sean Hallgren ◽  
Chris Leonardi ◽  
Travis Morrison ◽  
Jennifer Park
2021 ◽  
Vol 15 (1) ◽  
pp. 454-464
Author(s):  
Guanju Xiao ◽  
Lixia Luo ◽  
Yingpu Deng

Abstract Loops and cycles play an important role in computing endomorphism rings of supersingular elliptic curves and related cryptosystems. For a supersingular elliptic curve E defined over 𝔽 p 2 , if an imaginary quadratic order O can be embedded in End(E) and a prime L splits into two principal ideals in O, we construct loops or cycles in the supersingular L-isogeny graph at the vertices which are next to j(E) in the supersingular ℓ-isogeny graph where ℓ is a prime different from L. Next, we discuss the lengths of these cycles especially for j(E) = 1728 and 0. Finally, we also determine an upper bound on primes p for which there are unexpected 2-cycles if ℓ doesn’t split in O.


2012 ◽  
Vol 15 ◽  
pp. 317-325 ◽  
Author(s):  
Andrew V. Sutherland

AbstractGiven an elliptic curve E over a field of positive characteristic p, we consider how to efficiently determine whether E is ordinary or supersingular. We analyze the complexity of several existing algorithms and then present a new approach that exploits structural differences between ordinary and supersingular isogeny graphs. This yields a simple algorithm that, given E and a suitable non-residue in 𝔽p2, determines the supersingularity of E in O(n3log 2n) time and O(n) space, where n=O(log p) . Both these complexity bounds are significant improvements over existing methods, as we demonstrate with some practical computations.


2020 ◽  
Vol 14 (1) ◽  
pp. 414-437
Author(s):  
Leonardo Colò ◽  
David Kohel

AbstractWe introduce a category of 𝓞-oriented supersingular elliptic curves and derive properties of the associated oriented and nonoriented ℓ-isogeny supersingular isogeny graphs. As an application we introduce an oriented supersingular isogeny Diffie-Hellman protocol (OSIDH), analogous to the supersingular isogeny Diffie-Hellman (SIDH) protocol and generalizing the commutative supersingular isogeny Diffie-Hellman (CSIDH) protocol.


Sign in / Sign up

Export Citation Format

Share Document