ref: 7be7d0681f567e97fd37f937c2e5e486d6d74eab
dir: /sys/src/ape/lib/openssl/crypto/ec/ec2_smpt.c/
/* crypto/ec/ec2_smpt.c */
/* This code was originally written by Douglas Stebila
* <[email protected]> for the OpenSSL project.
*/
/* ====================================================================
* 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
* [email protected].
*
* 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
* ([email protected]). This product includes software written by Tim
* Hudson ([email protected]).
*
*/
/* Calaculates and sets the affine coordinates of an EC_POINT from the given
* compressed coordinates. Uses algorithm 2.3.4 of SEC 1.
* Note that the simple implementation only uses affine coordinates.
*
* This algorithm is patented by Certicom Corp. under US Patent 6,141,420
* (for licensing information, contact [email protected]).
* This function is disabled by default and can be enabled by defining the
* preprocessor macro OPENSSL_EC_BIN_PT_COMP at Configure-time.
*/
int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group, EC_POINT *point,
const BIGNUM *x_, int y_bit, BN_CTX *ctx)
{
#ifndef OPENSSL_EC_BIN_PT_COMP
ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_DISABLED);
return 0;
#else
BN_CTX *new_ctx = NULL;
BIGNUM *tmp, *x, *y, *z;
int ret = 0, z0;
/* clear error queue */
ERR_clear_error();
if (ctx == NULL)
{
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL)
return 0;
}
y_bit = (y_bit != 0) ? 1 : 0;
BN_CTX_start(ctx);
tmp = BN_CTX_get(ctx);
x = BN_CTX_get(ctx);
y = BN_CTX_get(ctx);
z = BN_CTX_get(ctx);
if (z == NULL) goto err;
if (!BN_GF2m_mod_arr(x, x_, group->poly)) goto err;
if (BN_is_zero(x))
{
if (!BN_GF2m_mod_sqrt_arr(y, &group->b, group->poly, ctx)) goto err;
}
else
{
if (!group->meth->field_sqr(group, tmp, x, ctx)) goto err;
if (!group->meth->field_div(group, tmp, &group->b, tmp, ctx)) goto err;
if (!BN_GF2m_add(tmp, &group->a, tmp)) goto err;
if (!BN_GF2m_add(tmp, x, tmp)) goto err;
if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx))
{
unsigned long err = ERR_peek_last_error();
if (ERR_GET_LIB(err) == ERR_LIB_BN && ERR_GET_REASON(err) == BN_R_NO_SOLUTION)
{
ERR_clear_error();
ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, EC_R_INVALID_COMPRESSED_POINT);
}
else
ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES, ERR_R_BN_LIB);
goto err;
}
z0 = (BN_is_odd(z)) ? 1 : 0;
if (!group->meth->field_mul(group, y, x, z, ctx)) goto err;
if (z0 != y_bit)
{
if (!BN_GF2m_add(y, y, x)) goto err;
}
}
if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx)) goto err;
ret = 1;
err:
BN_CTX_end(ctx);
if (new_ctx != NULL)
BN_CTX_free(new_ctx);
return ret;
#endif
}