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/* crypto/ec/ec_check.c */
/* ====================================================================
* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#include "ec_lcl.h"
#include <openssl/err.h>
int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
{
int ret = 0;
BIGNUM *order;
BN_CTX *new_ctx = NULL;
EC_POINT *point = NULL;
if (ctx == NULL)
{
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
{
ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
goto err;
}
}
BN_CTX_start(ctx);
if ((order = BN_CTX_get(ctx)) == NULL) goto err;
/* check the discriminant */
if (!EC_GROUP_check_discriminant(group, ctx))
{
ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
goto err;
}
/* check the generator */
if (group->generator == NULL)
{
ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
goto err;
}
if (!EC_POINT_is_on_curve(group, group->generator, ctx))
{
ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
goto err;
}
/* check the order of the generator */
if ((point = EC_POINT_new(group)) == NULL) goto err;
if (!EC_GROUP_get_order(group, order, ctx)) goto err;
if (BN_is_zero(order))
{
ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
goto err;
}
if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) goto err;
if (!EC_POINT_is_at_infinity(group, point))
{
ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
goto err;
}
ret = 1;
err:
if (ctx != NULL)
BN_CTX_end(ctx);
if (new_ctx != NULL)
BN_CTX_free(new_ctx);
if (point)
EC_POINT_free(point);
return ret;
}