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/*
* ecgen, tool for generating Elliptic curve domain parameters
* Copyright (C) 2017-2018 J08nY
*/
#include "metadata.h"
#include "field.h"
#include "gens.h"
GENERATOR(metadata_gen) {
pari_sp ltop = avma;
GEN j = field_elementi(ell_get_j(curve->curve));
GEN disc = field_elementi(ell_get_disc(curve->curve));
GEN embedding_degree;
GEN q;
if (typ(curve->field) == t_INT) {
embedding_degree = gens_get_embedding(curve->field, curve->order);
q = curve->field;
} else if (typ(curve->field) == t_FFELT) {
embedding_degree = NULL;
q = int2n(degree(FF_mod(curve->field)));
} else {
return -7;
}
GEN frobenius = subii(addis(q, 1), curve->order);
GEN conductor;
GEN cm_disc;
if (typ(curve->field) == t_INT) {
GEN d_f = coredisc2(subii(sqri(frobenius), mulis(q, 4)));
cm_disc = gcopy(gel(d_f, 1));
conductor = gcopy(gel(d_f, 2));
gerepileall(ltop, 6, &j, &disc, &embedding_degree, &frobenius, &cm_disc, &conductor);
} else if (typ(curve->field) == t_FFELT) {
cm_disc = NULL;
conductor = NULL;
gerepileall(ltop, 3, &j, &disc, &frobenius);
} else {
return -7;
}
curve->meta.j_invariant = j;
curve->meta.discriminant = disc;
curve->meta.embedding_degree = embedding_degree;
curve->meta.frobenius_trace = frobenius;
curve->meta.cm_discriminant = cm_disc;
curve->meta.conductor = conductor;
return 1;
}
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