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/*
* ecgen, tool for generating Elliptic curve domain parameters
* Copyright (C) 2017-2018 J08nY
*/
#include "gens.h"
#include "field.h"
#include "metadata.h"
GENERATOR(metadata_gen) {
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 = negi(subii(curve->order, addis(q, 1)));
GEN cm_disc;
if (typ(curve->field) == t_INT) {
cm_disc = core(subii(mulis(q, 4), sqri(frobenius)));
} else if (typ(curve->field) == t_FFELT){
cm_disc = NULL;
} 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;
return 1;
}
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