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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2010-2018. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
#include "ecdh.h"
#include "ec.h"
/*
(_OthersPublicKey, _MyPrivateKey)
(_OthersPublicKey, _MyEC_Point)
*/
ERL_NIF_TERM ecdh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
/* (OtherPublicKey, Curve, My) */
{
#if defined(HAVE_EC)
ERL_NIF_TERM ret;
unsigned char *p;
EC_KEY* key = NULL;
int degree;
size_t field_size;
EC_GROUP *group = NULL;
const BIGNUM *priv_key;
EC_POINT *my_ecpoint = NULL;
EC_KEY *other_ecdh = NULL;
if (argc != 3)
goto bad_arg;
if (!get_ec_key(env, argv[1], argv[2], atom_undefined, &key))
goto bad_arg;
if ((group = EC_GROUP_dup(EC_KEY_get0_group(key))) == NULL)
goto bad_arg;
priv_key = EC_KEY_get0_private_key(key);
if (!term2point(env, argv[0], group, &my_ecpoint)) {
goto err;
}
if ((other_ecdh = EC_KEY_new()) == NULL)
goto err;
if (!EC_KEY_set_group(other_ecdh, group))
goto err;
if (!EC_KEY_set_private_key(other_ecdh, priv_key))
goto err;
if ((degree = EC_GROUP_get_degree(group)) <= 0)
goto err;
field_size = (size_t)degree;
if ((p = enif_make_new_binary(env, (field_size+7)/8, &ret)) == NULL)
goto err;
if (ECDH_compute_key(p, (field_size+7)/8, my_ecpoint, other_ecdh, NULL) < 1)
goto err;
goto done;
bad_arg:
ret = make_badarg_maybe(env);
goto done;
err:
ret = enif_make_badarg(env);
done:
if (group)
EC_GROUP_free(group);
if (my_ecpoint)
EC_POINT_free(my_ecpoint);
if (other_ecdh)
EC_KEY_free(other_ecdh);
if (key)
EC_KEY_free(key);
return ret;
#else
return atom_notsup;
#endif
}
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