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1 /* Originally written by Bodo Moeller for the OpenSSL project.
2  * ====================================================================
3  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  *
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *    the documentation and/or other materials provided with the
15  *    distribution.
16  *
17  * 3. All advertising materials mentioning features or use of this
18  *    software must display the following acknowledgment:
19  *    "This product includes software developed by the OpenSSL Project
20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21  *
22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23  *    endorse or promote products derived from this software without
24  *    prior written permission. For written permission, please contact
25  *    openssl-core@openssl.org.
26  *
27  * 5. Products derived from this software may not be called "OpenSSL"
28  *    nor may "OpenSSL" appear in their names without prior written
29  *    permission of the OpenSSL Project.
30  *
31  * 6. Redistributions of any form whatsoever must retain the following
32  *    acknowledgment:
33  *    "This product includes software developed by the OpenSSL Project
34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35  *
36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47  * OF THE POSSIBILITY OF SUCH DAMAGE.
48  * ====================================================================
49  *
50  * This product includes cryptographic software written by Eric Young
51  * (eay@cryptsoft.com).  This product includes software written by Tim
52  * Hudson (tjh@cryptsoft.com).
53  *
54  */
55 /* ====================================================================
56  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
57  *
58  * Portions of the attached software ("Contribution") are developed by
59  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
60  *
61  * The Contribution is licensed pursuant to the OpenSSL open source
62  * license provided above.
63  *
64  * The elliptic curve binary polynomial software is originally written by
65  * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
66  * Laboratories. */
67 
68 #ifndef OPENSSL_HEADER_EC_H
69 #define OPENSSL_HEADER_EC_H
70 
71 #include <openssl/base.h>
72 
73 #if defined(__cplusplus)
74 extern "C" {
75 #endif
76 
77 
78 // Low-level operations on elliptic curves.
79 
80 
81 // point_conversion_form_t enumerates forms, as defined in X9.62 (ECDSA), for
82 // the encoding of a elliptic curve point (x,y)
83 typedef enum {
84   // POINT_CONVERSION_COMPRESSED indicates that the point is encoded as z||x,
85   // where the octet z specifies which solution of the quadratic equation y
86   // is.
87   POINT_CONVERSION_COMPRESSED = 2,
88 
89   // POINT_CONVERSION_UNCOMPRESSED indicates that the point is encoded as
90   // z||x||y, where z is the octet 0x04.
91   POINT_CONVERSION_UNCOMPRESSED = 4,
92 
93   // POINT_CONVERSION_HYBRID indicates that the point is encoded as z||x||y,
94   // where z specifies which solution of the quadratic equation y is. This is
95   // not supported by the code and has never been observed in use.
96   //
97   // TODO(agl): remove once node.js no longer references this.
98   POINT_CONVERSION_HYBRID = 6,
99 } point_conversion_form_t;
100 
101 
102 // Elliptic curve groups.
103 
104 // EC_GROUP_new_by_curve_name returns a fresh EC_GROUP object for the elliptic
105 // curve specified by |nid|, or NULL on error.
106 //
107 // The supported NIDs are:
108 //   NID_secp224r1,
109 //   NID_X9_62_prime256v1,
110 //   NID_secp384r1,
111 //   NID_secp521r1
112 OPENSSL_EXPORT EC_GROUP *EC_GROUP_new_by_curve_name(int nid);
113 
114 // EC_GROUP_free frees |group| and the data that it points to.
115 OPENSSL_EXPORT void EC_GROUP_free(EC_GROUP *group);
116 
117 // EC_GROUP_dup returns a fresh |EC_GROUP| which is equal to |a| or NULL on
118 // error.
119 OPENSSL_EXPORT EC_GROUP *EC_GROUP_dup(const EC_GROUP *a);
120 
121 // EC_GROUP_cmp returns zero if |a| and |b| are the same group and non-zero
122 // otherwise.
123 OPENSSL_EXPORT int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b,
124                                 BN_CTX *ignored);
125 
126 // EC_GROUP_get0_generator returns a pointer to the internal |EC_POINT| object
127 // in |group| that specifies the generator for the group.
128 OPENSSL_EXPORT const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group);
129 
130 // EC_GROUP_get0_order returns a pointer to the internal |BIGNUM| object in
131 // |group| that specifies the order of the group.
132 OPENSSL_EXPORT const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group);
133 
134 // EC_GROUP_get_cofactor sets |*cofactor| to the cofactor of |group| using
135 // |ctx|, if it's not NULL. It returns one on success and zero otherwise.
136 OPENSSL_EXPORT int EC_GROUP_get_cofactor(const EC_GROUP *group,
137                                          BIGNUM *cofactor, BN_CTX *ctx);
138 
139 // EC_GROUP_get_curve_GFp gets various parameters about a group. It sets
140 // |*out_p| to the order of the coordinate field and |*out_a| and |*out_b| to
141 // the parameters of the curve when expressed as y² = x³ + ax + b. Any of the
142 // output parameters can be NULL. It returns one on success and zero on
143 // error.
144 OPENSSL_EXPORT int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *out_p,
145                                           BIGNUM *out_a, BIGNUM *out_b,
146                                           BN_CTX *ctx);
147 
148 // EC_GROUP_get_curve_name returns a NID that identifies |group|.
149 OPENSSL_EXPORT int EC_GROUP_get_curve_name(const EC_GROUP *group);
150 
151 // EC_GROUP_get_degree returns the number of bits needed to represent an
152 // element of the field underlying |group|.
153 OPENSSL_EXPORT unsigned EC_GROUP_get_degree(const EC_GROUP *group);
154 
155 
156 // Points on elliptic curves.
157 
158 // EC_POINT_new returns a fresh |EC_POINT| object in the given group, or NULL
159 // on error.
160 OPENSSL_EXPORT EC_POINT *EC_POINT_new(const EC_GROUP *group);
161 
162 // EC_POINT_free frees |point| and the data that it points to.
163 OPENSSL_EXPORT void EC_POINT_free(EC_POINT *point);
164 
165 // EC_POINT_copy sets |*dest| equal to |*src|. It returns one on success and
166 // zero otherwise.
167 OPENSSL_EXPORT int EC_POINT_copy(EC_POINT *dest, const EC_POINT *src);
168 
169 // EC_POINT_dup returns a fresh |EC_POINT| that contains the same values as
170 // |src|, or NULL on error.
171 OPENSSL_EXPORT EC_POINT *EC_POINT_dup(const EC_POINT *src,
172                                       const EC_GROUP *group);
173 
174 // EC_POINT_set_to_infinity sets |point| to be the "point at infinity" for the
175 // given group.
176 OPENSSL_EXPORT int EC_POINT_set_to_infinity(const EC_GROUP *group,
177                                             EC_POINT *point);
178 
179 // EC_POINT_is_at_infinity returns one iff |point| is the point at infinity and
180 // zero otherwise.
181 OPENSSL_EXPORT int EC_POINT_is_at_infinity(const EC_GROUP *group,
182                                            const EC_POINT *point);
183 
184 // EC_POINT_is_on_curve returns one if |point| is an element of |group| and
185 // and zero otherwise or when an error occurs. This is different from OpenSSL,
186 // which returns -1 on error. If |ctx| is non-NULL, it may be used.
187 OPENSSL_EXPORT int EC_POINT_is_on_curve(const EC_GROUP *group,
188                                         const EC_POINT *point, BN_CTX *ctx);
189 
190 // EC_POINT_cmp returns zero if |a| is equal to |b|, greater than zero if
191 // not equal and -1 on error. If |ctx| is not NULL, it may be used.
192 OPENSSL_EXPORT int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a,
193                                 const EC_POINT *b, BN_CTX *ctx);
194 
195 // EC_POINT_make_affine converts |point| to affine form, internally. It returns
196 // one on success and zero otherwise. If |ctx| is not NULL, it may be used.
197 OPENSSL_EXPORT int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point,
198                                         BN_CTX *ctx);
199 
200 // EC_POINTs_make_affine converts |num| points from |points| to affine form,
201 // internally. It returns one on success and zero otherwise. If |ctx| is not
202 // NULL, it may be used.
203 OPENSSL_EXPORT int EC_POINTs_make_affine(const EC_GROUP *group, size_t num,
204                                          EC_POINT *points[], BN_CTX *ctx);
205 
206 
207 // Point conversion.
208 
209 // EC_POINT_get_affine_coordinates_GFp sets |x| and |y| to the affine value of
210 // |point| using |ctx|, if it's not NULL. It returns one on success and zero
211 // otherwise.
212 OPENSSL_EXPORT int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
213                                                        const EC_POINT *point,
214                                                        BIGNUM *x, BIGNUM *y,
215                                                        BN_CTX *ctx);
216 
217 // EC_POINT_set_affine_coordinates_GFp sets the value of |point| to be
218 // (|x|, |y|). The |ctx| argument may be used if not NULL. It returns one
219 // on success or zero on error. Note that, unlike with OpenSSL, it's
220 // considered an error if the point is not on the curve.
221 OPENSSL_EXPORT int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group,
222                                                        EC_POINT *point,
223                                                        const BIGNUM *x,
224                                                        const BIGNUM *y,
225                                                        BN_CTX *ctx);
226 
227 // EC_POINT_point2oct serialises |point| into the X9.62 form given by |form|
228 // into, at most, |len| bytes at |buf|. It returns the number of bytes written
229 // or zero on error if |buf| is non-NULL, else the number of bytes needed. The
230 // |ctx| argument may be used if not NULL.
231 OPENSSL_EXPORT size_t EC_POINT_point2oct(const EC_GROUP *group,
232                                          const EC_POINT *point,
233                                          point_conversion_form_t form,
234                                          uint8_t *buf, size_t len, BN_CTX *ctx);
235 
236 // EC_POINT_point2cbb behaves like |EC_POINT_point2oct| but appends the
237 // serialised point to |cbb|. It returns one on success and zero on error.
238 OPENSSL_EXPORT int EC_POINT_point2cbb(CBB *out, const EC_GROUP *group,
239                                       const EC_POINT *point,
240                                       point_conversion_form_t form,
241                                       BN_CTX *ctx);
242 
243 // EC_POINT_oct2point sets |point| from |len| bytes of X9.62 format
244 // serialisation in |buf|. It returns one on success and zero otherwise. The
245 // |ctx| argument may be used if not NULL.
246 OPENSSL_EXPORT int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *point,
247                                       const uint8_t *buf, size_t len,
248                                       BN_CTX *ctx);
249 
250 // EC_POINT_set_compressed_coordinates_GFp sets |point| to equal the point with
251 // the given |x| coordinate and the y coordinate specified by |y_bit| (see
252 // X9.62). It returns one on success and zero otherwise.
253 OPENSSL_EXPORT int EC_POINT_set_compressed_coordinates_GFp(
254     const EC_GROUP *group, EC_POINT *point, const BIGNUM *x, int y_bit,
255     BN_CTX *ctx);
256 
257 
258 // Group operations.
259 
260 // EC_POINT_add sets |r| equal to |a| plus |b|. It returns one on success and
261 // zero otherwise. If |ctx| is not NULL, it may be used.
262 OPENSSL_EXPORT int EC_POINT_add(const EC_GROUP *group, EC_POINT *r,
263                                 const EC_POINT *a, const EC_POINT *b,
264                                 BN_CTX *ctx);
265 
266 // EC_POINT_dbl sets |r| equal to |a| plus |a|. It returns one on success and
267 // zero otherwise. If |ctx| is not NULL, it may be used.
268 OPENSSL_EXPORT int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r,
269                                 const EC_POINT *a, BN_CTX *ctx);
270 
271 // EC_POINT_invert sets |a| equal to minus |a|. It returns one on success and
272 // zero otherwise. If |ctx| is not NULL, it may be used.
273 OPENSSL_EXPORT int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a,
274                                    BN_CTX *ctx);
275 
276 // EC_POINT_mul sets r = generator*n + q*m. It returns one on success and zero
277 // otherwise. If |ctx| is not NULL, it may be used.
278 OPENSSL_EXPORT int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r,
279                                 const BIGNUM *n, const EC_POINT *q,
280                                 const BIGNUM *m, BN_CTX *ctx);
281 
282 
283 // Deprecated functions.
284 
285 // EC_GROUP_new_curve_GFp creates a new, arbitrary elliptic curve group based
286 // on the equation y² = x³ + a·x + b. It returns the new group or NULL on
287 // error.
288 //
289 // This new group has no generator. It is an error to use a generator-less group
290 // with any functions except for |EC_GROUP_free|, |EC_POINT_new|,
291 // |EC_POINT_set_affine_coordinates_GFp|, and |EC_GROUP_set_generator|.
292 //
293 // |EC_GROUP|s returned by this function will always compare as unequal via
294 // |EC_GROUP_cmp| (even to themselves). |EC_GROUP_get_curve_name| will always
295 // return |NID_undef|.
296 //
297 // Avoid using arbitrary curves and use |EC_GROUP_new_by_curve_name| instead.
298 OPENSSL_EXPORT EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p,
299                                                 const BIGNUM *a,
300                                                 const BIGNUM *b, BN_CTX *ctx);
301 
302 // EC_GROUP_set_generator sets the generator for |group| to |generator|, which
303 // must have the given order and cofactor. It may only be used with |EC_GROUP|
304 // objects returned by |EC_GROUP_new_curve_GFp| and may only be used once on
305 // each group. |generator| must have been created using |group|.
306 OPENSSL_EXPORT int EC_GROUP_set_generator(EC_GROUP *group,
307                                           const EC_POINT *generator,
308                                           const BIGNUM *order,
309                                           const BIGNUM *cofactor);
310 
311 // EC_GROUP_get_order sets |*order| to the order of |group|, if it's not
312 // NULL. It returns one on success and zero otherwise. |ctx| is ignored. Use
313 // |EC_GROUP_get0_order| instead.
314 OPENSSL_EXPORT int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order,
315                                       BN_CTX *ctx);
316 
317 // EC_GROUP_set_asn1_flag does nothing.
318 OPENSSL_EXPORT void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag);
319 
320 #define OPENSSL_EC_NAMED_CURVE 0
321 
322 typedef struct ec_method_st EC_METHOD;
323 
324 // EC_GROUP_method_of returns NULL.
325 OPENSSL_EXPORT const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group);
326 
327 // EC_METHOD_get_field_type returns NID_X9_62_prime_field.
328 OPENSSL_EXPORT int EC_METHOD_get_field_type(const EC_METHOD *meth);
329 
330 // EC_GROUP_set_point_conversion_form aborts the process if |form| is not
331 // |POINT_CONVERSION_UNCOMPRESSED| and otherwise does nothing.
332 OPENSSL_EXPORT void EC_GROUP_set_point_conversion_form(
333     EC_GROUP *group, point_conversion_form_t form);
334 
335 // EC_builtin_curve describes a supported elliptic curve.
336 typedef struct {
337   int nid;
338   const char *comment;
339 } EC_builtin_curve;
340 
341 // EC_get_builtin_curves writes at most |max_num_curves| elements to
342 // |out_curves| and returns the total number that it would have written, had
343 // |max_num_curves| been large enough.
344 //
345 // The |EC_builtin_curve| items describe the supported elliptic curves.
346 OPENSSL_EXPORT size_t EC_get_builtin_curves(EC_builtin_curve *out_curves,
347                                             size_t max_num_curves);
348 
349 // EC_POINT_clear_free calls |EC_POINT_free|.
350 OPENSSL_EXPORT void EC_POINT_clear_free(EC_POINT *point);
351 
352 // Old code expects to get EC_KEY from ec.h.
353 #include <openssl/ec_key.h>
354 
355 
356 #if defined(__cplusplus)
357 }  // extern C
358 
359 extern "C++" {
360 
361 namespace bssl {
362 
363 BORINGSSL_MAKE_DELETER(EC_POINT, EC_POINT_free)
364 BORINGSSL_MAKE_DELETER(EC_GROUP, EC_GROUP_free)
365 
366 }  // namespace bssl
367 
368 }  // extern C++
369 
370 #endif
371 
372 #define EC_R_BUFFER_TOO_SMALL 100
373 #define EC_R_COORDINATES_OUT_OF_RANGE 101
374 #define EC_R_D2I_ECPKPARAMETERS_FAILURE 102
375 #define EC_R_EC_GROUP_NEW_BY_NAME_FAILURE 103
376 #define EC_R_GROUP2PKPARAMETERS_FAILURE 104
377 #define EC_R_I2D_ECPKPARAMETERS_FAILURE 105
378 #define EC_R_INCOMPATIBLE_OBJECTS 106
379 #define EC_R_INVALID_COMPRESSED_POINT 107
380 #define EC_R_INVALID_COMPRESSION_BIT 108
381 #define EC_R_INVALID_ENCODING 109
382 #define EC_R_INVALID_FIELD 110
383 #define EC_R_INVALID_FORM 111
384 #define EC_R_INVALID_GROUP_ORDER 112
385 #define EC_R_INVALID_PRIVATE_KEY 113
386 #define EC_R_MISSING_PARAMETERS 114
387 #define EC_R_MISSING_PRIVATE_KEY 115
388 #define EC_R_NON_NAMED_CURVE 116
389 #define EC_R_NOT_INITIALIZED 117
390 #define EC_R_PKPARAMETERS2GROUP_FAILURE 118
391 #define EC_R_POINT_AT_INFINITY 119
392 #define EC_R_POINT_IS_NOT_ON_CURVE 120
393 #define EC_R_SLOT_FULL 121
394 #define EC_R_UNDEFINED_GENERATOR 122
395 #define EC_R_UNKNOWN_GROUP 123
396 #define EC_R_UNKNOWN_ORDER 124
397 #define EC_R_WRONG_ORDER 125
398 #define EC_R_BIGNUM_OUT_OF_RANGE 126
399 #define EC_R_WRONG_CURVE_PARAMETERS 127
400 #define EC_R_DECODE_ERROR 128
401 #define EC_R_ENCODE_ERROR 129
402 #define EC_R_GROUP_MISMATCH 130
403 #define EC_R_INVALID_COFACTOR 131
404 #define EC_R_PUBLIC_KEY_VALIDATION_FAILED 132
405 #define EC_R_INVALID_SCALAR 133
406 
407 #endif  // OPENSSL_HEADER_EC_H
408