source: EcnlProtoTool/trunk/openssl-1.1.0e/crypto/ec/ec2_oct.c@ 331

Last change on this file since 331 was 331, checked in by coas-nagasima, 6 years ago

prototoolに関連するプロジェクトをnewlibからmuslを使うよう変更・更新
ntshellをnewlibの下位の実装から、muslのsyscallの実装に変更・更新
以下のOSSをアップデート
・mruby-1.3.0
・musl-1.1.18
・onigmo-6.1.3
・tcc-0.9.27
以下のOSSを追加
・openssl-1.1.0e
・curl-7.57.0
・zlib-1.2.11
以下のmrbgemsを追加
・iij/mruby-digest
・iij/mruby-env
・iij/mruby-errno
・iij/mruby-iijson
・iij/mruby-ipaddr
・iij/mruby-mock
・iij/mruby-require
・iij/mruby-tls-openssl
  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/x-csrc
File size: 10.0 KB
Line 
1/*
2 * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10/* ====================================================================
11 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
12 *
13 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
14 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
15 * to the OpenSSL project.
16 *
17 * The ECC Code is licensed pursuant to the OpenSSL open source
18 * license provided below.
19 *
20 * The software is originally written by Sheueling Chang Shantz and
21 * Douglas Stebila of Sun Microsystems Laboratories.
22 *
23 */
24
25#include <openssl/err.h>
26
27#include "ec_lcl.h"
28
29#ifndef OPENSSL_NO_EC2M
30
31/*-
32 * Calculates and sets the affine coordinates of an EC_POINT from the given
33 * compressed coordinates. Uses algorithm 2.3.4 of SEC 1.
34 * Note that the simple implementation only uses affine coordinates.
35 *
36 * The method is from the following publication:
37 *
38 * Harper, Menezes, Vanstone:
39 * "Public-Key Cryptosystems with Very Small Key Lengths",
40 * EUROCRYPT '92, Springer-Verlag LNCS 658,
41 * published February 1993
42 *
43 * US Patents 6,141,420 and 6,618,483 (Vanstone, Mullin, Agnew) describe
44 * the same method, but claim no priority date earlier than July 29, 1994
45 * (and additionally fail to cite the EUROCRYPT '92 publication as prior art).
46 */
47int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *group,
48 EC_POINT *point,
49 const BIGNUM *x_, int y_bit,
50 BN_CTX *ctx)
51{
52 BN_CTX *new_ctx = NULL;
53 BIGNUM *tmp, *x, *y, *z;
54 int ret = 0, z0;
55
56 /* clear error queue */
57 ERR_clear_error();
58
59 if (ctx == NULL) {
60 ctx = new_ctx = BN_CTX_new();
61 if (ctx == NULL)
62 return 0;
63 }
64
65 y_bit = (y_bit != 0) ? 1 : 0;
66
67 BN_CTX_start(ctx);
68 tmp = BN_CTX_get(ctx);
69 x = BN_CTX_get(ctx);
70 y = BN_CTX_get(ctx);
71 z = BN_CTX_get(ctx);
72 if (z == NULL)
73 goto err;
74
75 if (!BN_GF2m_mod_arr(x, x_, group->poly))
76 goto err;
77 if (BN_is_zero(x)) {
78 if (!BN_GF2m_mod_sqrt_arr(y, group->b, group->poly, ctx))
79 goto err;
80 } else {
81 if (!group->meth->field_sqr(group, tmp, x, ctx))
82 goto err;
83 if (!group->meth->field_div(group, tmp, group->b, tmp, ctx))
84 goto err;
85 if (!BN_GF2m_add(tmp, group->a, tmp))
86 goto err;
87 if (!BN_GF2m_add(tmp, x, tmp))
88 goto err;
89 if (!BN_GF2m_mod_solve_quad_arr(z, tmp, group->poly, ctx)) {
90 unsigned long err = ERR_peek_last_error();
91
92 if (ERR_GET_LIB(err) == ERR_LIB_BN
93 && ERR_GET_REASON(err) == BN_R_NO_SOLUTION) {
94 ERR_clear_error();
95 ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES,
96 EC_R_INVALID_COMPRESSED_POINT);
97 } else
98 ECerr(EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES,
99 ERR_R_BN_LIB);
100 goto err;
101 }
102 z0 = (BN_is_odd(z)) ? 1 : 0;
103 if (!group->meth->field_mul(group, y, x, z, ctx))
104 goto err;
105 if (z0 != y_bit) {
106 if (!BN_GF2m_add(y, y, x))
107 goto err;
108 }
109 }
110
111 if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
112 goto err;
113
114 ret = 1;
115
116 err:
117 BN_CTX_end(ctx);
118 BN_CTX_free(new_ctx);
119 return ret;
120}
121
122/*
123 * Converts an EC_POINT to an octet string. If buf is NULL, the encoded
124 * length will be returned. If the length len of buf is smaller than required
125 * an error will be returned.
126 */
127size_t ec_GF2m_simple_point2oct(const EC_GROUP *group, const EC_POINT *point,
128 point_conversion_form_t form,
129 unsigned char *buf, size_t len, BN_CTX *ctx)
130{
131 size_t ret;
132 BN_CTX *new_ctx = NULL;
133 int used_ctx = 0;
134 BIGNUM *x, *y, *yxi;
135 size_t field_len, i, skip;
136
137 if ((form != POINT_CONVERSION_COMPRESSED)
138 && (form != POINT_CONVERSION_UNCOMPRESSED)
139 && (form != POINT_CONVERSION_HYBRID)) {
140 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_INVALID_FORM);
141 goto err;
142 }
143
144 if (EC_POINT_is_at_infinity(group, point)) {
145 /* encodes to a single 0 octet */
146 if (buf != NULL) {
147 if (len < 1) {
148 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
149 return 0;
150 }
151 buf[0] = 0;
152 }
153 return 1;
154 }
155
156 /* ret := required output buffer length */
157 field_len = (EC_GROUP_get_degree(group) + 7) / 8;
158 ret =
159 (form ==
160 POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
161
162 /* if 'buf' is NULL, just return required length */
163 if (buf != NULL) {
164 if (len < ret) {
165 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, EC_R_BUFFER_TOO_SMALL);
166 goto err;
167 }
168
169 if (ctx == NULL) {
170 ctx = new_ctx = BN_CTX_new();
171 if (ctx == NULL)
172 return 0;
173 }
174
175 BN_CTX_start(ctx);
176 used_ctx = 1;
177 x = BN_CTX_get(ctx);
178 y = BN_CTX_get(ctx);
179 yxi = BN_CTX_get(ctx);
180 if (yxi == NULL)
181 goto err;
182
183 if (!EC_POINT_get_affine_coordinates_GF2m(group, point, x, y, ctx))
184 goto err;
185
186 buf[0] = form;
187 if ((form != POINT_CONVERSION_UNCOMPRESSED) && !BN_is_zero(x)) {
188 if (!group->meth->field_div(group, yxi, y, x, ctx))
189 goto err;
190 if (BN_is_odd(yxi))
191 buf[0]++;
192 }
193
194 i = 1;
195
196 skip = field_len - BN_num_bytes(x);
197 if (skip > field_len) {
198 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
199 goto err;
200 }
201 while (skip > 0) {
202 buf[i++] = 0;
203 skip--;
204 }
205 skip = BN_bn2bin(x, buf + i);
206 i += skip;
207 if (i != 1 + field_len) {
208 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
209 goto err;
210 }
211
212 if (form == POINT_CONVERSION_UNCOMPRESSED
213 || form == POINT_CONVERSION_HYBRID) {
214 skip = field_len - BN_num_bytes(y);
215 if (skip > field_len) {
216 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
217 goto err;
218 }
219 while (skip > 0) {
220 buf[i++] = 0;
221 skip--;
222 }
223 skip = BN_bn2bin(y, buf + i);
224 i += skip;
225 }
226
227 if (i != ret) {
228 ECerr(EC_F_EC_GF2M_SIMPLE_POINT2OCT, ERR_R_INTERNAL_ERROR);
229 goto err;
230 }
231 }
232
233 if (used_ctx)
234 BN_CTX_end(ctx);
235 BN_CTX_free(new_ctx);
236 return ret;
237
238 err:
239 if (used_ctx)
240 BN_CTX_end(ctx);
241 BN_CTX_free(new_ctx);
242 return 0;
243}
244
245/*
246 * Converts an octet string representation to an EC_POINT. Note that the
247 * simple implementation only uses affine coordinates.
248 */
249int ec_GF2m_simple_oct2point(const EC_GROUP *group, EC_POINT *point,
250 const unsigned char *buf, size_t len,
251 BN_CTX *ctx)
252{
253 point_conversion_form_t form;
254 int y_bit;
255 BN_CTX *new_ctx = NULL;
256 BIGNUM *x, *y, *yxi;
257 size_t field_len, enc_len;
258 int ret = 0;
259
260 if (len == 0) {
261 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_BUFFER_TOO_SMALL);
262 return 0;
263 }
264 form = buf[0];
265 y_bit = form & 1;
266 form = form & ~1U;
267 if ((form != 0) && (form != POINT_CONVERSION_COMPRESSED)
268 && (form != POINT_CONVERSION_UNCOMPRESSED)
269 && (form != POINT_CONVERSION_HYBRID)) {
270 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
271 return 0;
272 }
273 if ((form == 0 || form == POINT_CONVERSION_UNCOMPRESSED) && y_bit) {
274 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
275 return 0;
276 }
277
278 if (form == 0) {
279 if (len != 1) {
280 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
281 return 0;
282 }
283
284 return EC_POINT_set_to_infinity(group, point);
285 }
286
287 field_len = (EC_GROUP_get_degree(group) + 7) / 8;
288 enc_len =
289 (form ==
290 POINT_CONVERSION_COMPRESSED) ? 1 + field_len : 1 + 2 * field_len;
291
292 if (len != enc_len) {
293 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
294 return 0;
295 }
296
297 if (ctx == NULL) {
298 ctx = new_ctx = BN_CTX_new();
299 if (ctx == NULL)
300 return 0;
301 }
302
303 BN_CTX_start(ctx);
304 x = BN_CTX_get(ctx);
305 y = BN_CTX_get(ctx);
306 yxi = BN_CTX_get(ctx);
307 if (yxi == NULL)
308 goto err;
309
310 if (!BN_bin2bn(buf + 1, field_len, x))
311 goto err;
312 if (BN_ucmp(x, group->field) >= 0) {
313 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
314 goto err;
315 }
316
317 if (form == POINT_CONVERSION_COMPRESSED) {
318 if (!EC_POINT_set_compressed_coordinates_GF2m
319 (group, point, x, y_bit, ctx))
320 goto err;
321 } else {
322 if (!BN_bin2bn(buf + 1 + field_len, field_len, y))
323 goto err;
324 if (BN_ucmp(y, group->field) >= 0) {
325 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
326 goto err;
327 }
328 if (form == POINT_CONVERSION_HYBRID) {
329 if (!group->meth->field_div(group, yxi, y, x, ctx))
330 goto err;
331 if (y_bit != BN_is_odd(yxi)) {
332 ECerr(EC_F_EC_GF2M_SIMPLE_OCT2POINT, EC_R_INVALID_ENCODING);
333 goto err;
334 }
335 }
336
337 /*
338 * EC_POINT_set_affine_coordinates_GF2m is responsible for checking that
339 * the point is on the curve.
340 */
341 if (!EC_POINT_set_affine_coordinates_GF2m(group, point, x, y, ctx))
342 goto err;
343 }
344
345 ret = 1;
346
347 err:
348 BN_CTX_end(ctx);
349 BN_CTX_free(new_ctx);
350 return ret;
351}
352#endif
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