1 /* crypto/ec/ecp_oct.c */
3 * Includes code written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
4 * for the OpenSSL project. Includes code written by Bodo Moeller for the
7 /* ====================================================================
8 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in
19 * the documentation and/or other materials provided with the
22 * 3. All advertising materials mentioning features or use of this
23 * software must display the following acknowledgment:
24 * "This product includes software developed by the OpenSSL Project
25 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
27 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
28 * endorse or promote products derived from this software without
29 * prior written permission. For written permission, please contact
30 * openssl-core@openssl.org.
32 * 5. Products derived from this software may not be called "OpenSSL"
33 * nor may "OpenSSL" appear in their names without prior written
34 * permission of the OpenSSL Project.
36 * 6. Redistributions of any form whatsoever must retain the following
38 * "This product includes software developed by the OpenSSL Project
39 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
41 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
42 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
44 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
47 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
48 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
49 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
50 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
51 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
52 * OF THE POSSIBILITY OF SUCH DAMAGE.
53 * ====================================================================
55 * This product includes cryptographic software written by Eric Young
56 * (eay@cryptsoft.com). This product includes software written by Tim
57 * Hudson (tjh@cryptsoft.com).
60 /* ====================================================================
61 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
62 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
63 * and contributed to the OpenSSL project.
66 #include <openssl/err.h>
67 #include <openssl/symhacks.h>
71 int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *group,
73 const BIGNUM *x_, int y_bit,
76 BN_CTX *new_ctx = NULL;
77 BIGNUM *tmp1, *tmp2, *x, *y;
80 /* clear error queue */
84 ctx = new_ctx = BN_CTX_new();
92 tmp1 = BN_CTX_get(ctx);
93 tmp2 = BN_CTX_get(ctx);
100 * Recover y. We have a Weierstrass equation
101 * y^2 = x^3 + a*x + b,
102 * so y is one of the square roots of x^3 + a*x + b.
106 if (!BN_nnmod(x, x_, &group->field, ctx))
108 if (group->meth->field_decode == 0) {
109 /* field_{sqr,mul} work on standard representation */
110 if (!group->meth->field_sqr(group, tmp2, x_, ctx))
112 if (!group->meth->field_mul(group, tmp1, tmp2, x_, ctx))
115 if (!BN_mod_sqr(tmp2, x_, &group->field, ctx))
117 if (!BN_mod_mul(tmp1, tmp2, x_, &group->field, ctx))
121 /* tmp1 := tmp1 + a*x */
122 if (group->a_is_minus3) {
123 if (!BN_mod_lshift1_quick(tmp2, x, &group->field))
125 if (!BN_mod_add_quick(tmp2, tmp2, x, &group->field))
127 if (!BN_mod_sub_quick(tmp1, tmp1, tmp2, &group->field))
130 if (group->meth->field_decode) {
131 if (!group->meth->field_decode(group, tmp2, &group->a, ctx))
133 if (!BN_mod_mul(tmp2, tmp2, x, &group->field, ctx))
136 /* field_mul works on standard representation */
137 if (!group->meth->field_mul(group, tmp2, &group->a, x, ctx))
141 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
145 /* tmp1 := tmp1 + b */
146 if (group->meth->field_decode) {
147 if (!group->meth->field_decode(group, tmp2, &group->b, ctx))
149 if (!BN_mod_add_quick(tmp1, tmp1, tmp2, &group->field))
152 if (!BN_mod_add_quick(tmp1, tmp1, &group->b, &group->field))
156 if (!BN_mod_sqrt(y, tmp1, &group->field, ctx)) {
157 unsigned long err = ERR_peek_last_error();
159 if (ERR_GET_LIB(err) == ERR_LIB_BN
160 && ERR_GET_REASON(err) == BN_R_NOT_A_SQUARE) {
162 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
163 EC_R_INVALID_COMPRESSED_POINT);
165 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
170 if (y_bit != BN_is_odd(y)) {
174 kron = BN_kronecker(x, &group->field, ctx);
179 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
180 EC_R_INVALID_COMPRESSION_BIT);
183 * BN_mod_sqrt() should have cought this error (not a square)
185 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
186 EC_R_INVALID_COMPRESSED_POINT);
189 if (!BN_usub(y, &group->field, y))
192 if (y_bit != BN_is_odd(y)) {
193 ECerr(EC_F_EC_GFP_SIMPLE_SET_COMPRESSED_COORDINATES,
194 ERR_R_INTERNAL_ERROR);
198 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
206 BN_CTX_free(new_ctx);
210 size_t ec_GFp_simple_point2oct(const EC_GROUP *group, const EC_POINT *point,
211 point_conversion_form_t form,
212 unsigned char *buf, size_t len, BN_CTX *ctx)
215 BN_CTX *new_ctx = NULL;
218 size_t field_len, i, skip;
220 if ((form != POINT_CONVERSION_COMPRESSED)
221 && (form != POINT_CONVERSION_UNCOMPRESSED)
222 && (form != POINT_CONVERSION_HYBRID)) {
223 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
227 if (EC_POINT_is_at_infinity(group, point)) {
228 /* encodes to a single 0 octet */
231 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
239 /* ret := required output buffer length */
240 field_len = BN_num_bytes(&group->field);
243 POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
245 /* if 'buf' is NULL, just return required length */
248 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
253 ctx = new_ctx = BN_CTX_new();
265 if (!EC_POINT_get_affine_coordinates_GFp(group, point, x, y, ctx))
268 if ((form == POINT_CONVERSION_COMPRESSED
269 || form == POINT_CONVERSION_HYBRID) && BN_is_odd(y))
276 skip = field_len - BN_num_bytes(x);
277 if (skip > field_len) {
278 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
285 skip = BN_bn2bin(x, buf + i);
287 if (i != 1 + field_len) {
288 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
292 if (form == POINT_CONVERSION_UNCOMPRESSED
293 || form == POINT_CONVERSION_HYBRID) {
294 skip = field_len - BN_num_bytes(y);
295 if (skip > field_len) {
296 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
303 skip = BN_bn2bin(y, buf + i);
308 ECerr(EC_F_EC_GFP_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
316 BN_CTX_free(new_ctx);
323 BN_CTX_free(new_ctx);
327 int ec_GFp_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
328 const unsigned char *buf, size_t len, BN_CTX *ctx)
330 point_conversion_form_t form;
332 BN_CTX *new_ctx = NULL;
334 size_t field_len, enc_len;
338 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
344 if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
345 && (form != POINT_CONVERSION_UNCOMPRESSED)
346 && (form != POINT_CONVERSION_HYBRID)) {
347 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
350 if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
351 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
357 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
361 return EC_POINT_set_to_infinity(group, point);
364 field_len = BN_num_bytes(&group->field);
367 POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
369 if (len != enc_len) {
370 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
375 ctx = new_ctx = BN_CTX_new();
386 if (!BN_bin2bn(buf + 1, field_len, x))
388 if (BN_ucmp(x, &group->field) >= 0) {
389 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
393 if (form == POINT_CONVERSION_COMPRESSED) {
394 if (!EC_POINT_set_compressed_coordinates_GFp
395 (group, point, x, y_bit, ctx))
398 if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
400 if (BN_ucmp(y, &group->field) >= 0) {
401 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
404 if (form == POINT_CONVERSION_HYBRID) {
405 if (y_bit != BN_is_odd(y)) {
406 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
411 if (!EC_POINT_set_affine_coordinates_GFp(group, point, x, y, ctx))
415 /* test required by X9.62 */
416 if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
417 ECerr(EC_F_EC_GFP_SIMPLE_OCT2POINT, EC_R_POINT_IS_NOT_ON_CURVE);
426 BN_CTX_free(new_ctx);