/*
* Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include "ec_lcl.h"
#include <openssl/err.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>
#include "internal/nelem.h"
int EC_GROUP_get_basis_type(const EC_GROUP *group)
{
int i;
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_characteristic_two_field)
/* everything else is currently not supported */
return 0;
/* Find the last non-zero element of group->poly[] */
for (i = 0;
i < (int)OSSL_NELEM(group->poly) && group->poly[i] != 0;
i++)
continue;
if (i == 4)
return NID_X9_62_ppBasis;
else if (i == 2)
return NID_X9_62_tpBasis;
else
/* everything else is currently not supported */
return 0;
}
#ifndef OPENSSL_NO_EC2M
int EC_GROUP_get_trinomial_basis(const EC_GROUP *group, unsigned int *k)
{
if (group == NULL)
return 0;
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_characteristic_two_field
|| !((group->poly[0] != 0) && (group->poly[1] != 0)
&& (group->poly[2] == 0))) {
ECerr(EC_F_EC_GROUP_GET_TRINOMIAL_BASIS,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (k)
*k = group->poly[1];
return 1;
}
int EC_GROUP_get_pentanomial_basis(const EC_GROUP *group, unsigned int *k1,
unsigned int *k2, unsigned int *k3)
{
if (group == NULL)
return 0;
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
NID_X9_62_characteristic_two_field
|| !((group->poly[0] != 0) && (group->poly[1] != 0)
&& (group->poly[2] != 0) && (group->poly[3] != 0)
&& (group->poly[4] == 0))) {
ECerr(EC_F_EC_GROUP_GET_PENTANOMIAL_BASIS,
ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
return 0;
}
if (k1)
*k1 = group->poly[3];
if (k2)
*k2 <