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/*
* ecgen, tool for generating Elliptic curve domain parameters
* Copyright (C) 2017 J08nY
*/
#include "gens.h"
#include "exhaustive/arg.h"
#include "point.h"
static int gens_put(curve_t *curve, GEN generators, long len) {
curve->generators = points_new((size_t)len);
curve->ngens = (size_t)len;
for (long i = 1; i <= len; ++i) {
point_t *p = point_new();
p->point = gel(generators, i);
p->order = ellorder(curve->curve, p->point, NULL);
p->cofactor = divii(curve->order, p->order);
curve->generators[i - 1] = p;
}
return 1;
}
GENERATOR(gens_gen_any) {
GEN generators = ellff_get_gens(curve->curve);
long len = glength(generators);
return gens_put(curve, generators, len);
}
GENERATOR(gens_gen_one) {
pari_sp ltop = avma;
GEN generators = ellff_get_gens(curve->curve);
long len = glength(generators);
if (len == 2) {
avma = ltop;
return -5;
}
return gens_put(curve, generators, len);
}
CHECK(gens_check_anomalous) {
if (cfg->field == FIELD_BINARY) return 1;
for (size_t i = 0; i < curve->ngens; ++i) {
if (mpcmp(curve->field, curve->generators[i]->order) == 0) {
return -5;
}
}
return 1;
}
GEN gens_get_embedding(GEN prime, GEN order) {
pari_sp ltop = avma;
GEN degree = gen_0;
GEN power = gen_1;
GEN pm;
do {
degree = addii(degree, gen_1);
power = mulii(power, prime);
pm = subii(power, gen_1);
} while (!dvdii(pm, order));
return gerepilecopy(ltop, degree);
}
CHECK(gens_check_embedding) {
HAS_ARG(args);
if (cfg->field == FIELD_BINARY) return 1;
pari_sp ltop = avma;
const char *min_degree = args->args;
GEN mind = strtoi(min_degree);
for (size_t i = 0; i < curve->ngens; ++i) {
GEN power =
gens_get_embedding(curve->field, curve->generators[i]->order);
if (mpcmp(power, mind) <= 0) {
avma = ltop;
return -5;
}
}
avma = ltop;
return 1;
}
UNROLL(gens_unroll) {
if (curve->generators) {
points_free_deep(&curve->generators, curve->ngens);
}
return -1;
}
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