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/*
* ecgen, tool for generating Elliptic curve domain parameters
* Copyright (C) 2017 J08nY
*/
#include "order.h"
#include "exhaustive/arg.h"
#include "io/input.h"
GENERATOR(order_gen_input) {
pari_sp ltop = avma;
GEN ord = input_int("order", cfg->bits);
if (gequalm1(ord)) {
avma = ltop;
return -4;
} else {
curve->order = ord;
obj_insert_shallow(curve->curve, 1, ord);
return 1;
}
}
GENERATOR(order_gen_any) {
GEN ord = ellff_get_card(curve->curve);
if (isclone(ord)) {
curve->order = gcopy(ord);
} else {
curve->order = ord;
}
return 1;
}
GENERATOR(order_gen_sea) {
pari_sp ltop = avma;
GEN order = ellsea(curve->curve, 0);
if (gequal0(order)) {
avma = ltop;
return -4;
} else {
curve->order = order;
obj_insert_shallow(curve->curve, 1, order);
return 1;
}
}
GENERATOR(order_gen_smallfact) {
HAS_ARG(args);
pari_ulong smallfact = *(pari_ulong *)args->args;
pari_sp ltop = avma;
GEN fact = mpfact(smallfact);
pari_ulong lfact = 0;
if (lgefint(fact) > 3) {
lfact = 0;
} else {
lfact = itou(fact);
}
GEN order = ellsea(curve->curve, lfact);
if (gequal0(order)) {
avma = ltop;
return -4;
}
GEN factors = factor(order);
GEN primes = gel(factors, 1);
GEN powers = gel(factors, 2);
long len = glength(primes);
GEN total = gen_1;
for (long i = 1; i < len; ++i) {
GEN pow = powii(gel(primes, i), gel(powers, i));
total = mulii(total, pow);
if (abscmpiu(total, smallfact) > 0) {
avma = ltop;
return -4;
}
}
curve->order = gerepileupto(ltop, order);
obj_insert_shallow(curve->curve, 1, curve->order);
return 1;
}
GENERATOR(order_gen_prime) {
pari_sp ltop = avma;
GEN order = ellsea(curve->curve, 1);
if (gequal0(order) || !(isprime(order))) {
avma = ltop;
return -4;
} else {
curve->order = order;
obj_insert_shallow(curve->curve, 1, curve->order);
return 1;
}
}
CHECK(order_check_pohlig_hellman) {
HAS_ARG(args);
pari_sp ltop = avma;
const char *min_fact = args->args;
GEN minf = strtoi(min_fact);
GEN factors = factor(curve->order);
GEN primes = gel(factors, 1);
long len = glength(primes);
if (mpcmp(gel(primes, len), minf) <= 0) {
avma = ltop;
return -4;
} else {
avma = ltop;
return 1;
}
}
CHECK(order_check_discriminant) {
HAS_ARG(args);
if (cfg->field == FIELD_BINARY) return 1;
pari_sp ltop = avma;
const char *min_disc = args->args;
GEN mind = strtoi(min_disc);
GEN t = negi(subii(curve->order, addii(curve->field, gen_1)));
GEN tp = subii(sqri(t), mulis(curve->field, 4));
GEN tp_factors = factor(tp);
GEN tp_primes = gel(tp_factors, 1);
GEN tp_pows = gel(tp_factors, 2);
long tp_pow_len = glength(tp_pows);
GEN value = gen_1;
for (long i = 1; i <= tp_pow_len; ++i) {
if (!dvdis(gel(tp_pows, i), 2)) {
continue;
}
GEN one_value = powii(gel(tp_primes, i), divis(gel(tp_pows, i), 2));
muliiz(value, one_value, value);
}
GEN s = value;
GEN D = divii(tp, s);
if (mod4(D) != 1) {
D = mulis(D, 4);
}
if (abscmpii(D, mind) <= 0) {
avma = ltop;
return -4;
}
avma = ltop;
return 1;
}
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