#!/usr/bin/env sage import sys from sage.all import * r = 21888242871839275222246405745257275088548364400416034343698204186575808495617 F = GF(r) b = 7950939520449436327800262930799465135910802758673292356620796789196167463969 btwist = F(b)*125 print "b =", b print "btwist =", btwist E = EllipticCurve(F, [-3, b]) print E Ec = E.cardinality() print "Ec =", Ec assert(Ec in Primes()) Et = EllipticCurve(F, [-75, btwist]) print Et Etc = Et.cardinality() print "Etc =", Etc assert(Etc in Primes()) assert(Ec + Etc == 2*r+2)