1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/* crypto/ec/ec2_smpt.c */
/* This code was originally written by Douglas Stebila
* <dstebila@student.math.uwaterloo.ca> 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
* 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).
*
*/
/* 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 licensing@certicom.com).
* 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;
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)) 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
}
|