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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 unsupported NID or allocation failure.
106 //
107 // The supported NIDs are:
108 //   NID_secp224r1 (P-224),
109 //   NID_X9_62_prime256v1 (P-256),
110 //   NID_secp384r1 (P-384),
111 //   NID_secp521r1 (P-521)
112 //
113 // If in doubt, use |NID_X9_62_prime256v1|, or see the curve25519.h header for
114 // more modern primitives.
115 OPENSSL_EXPORT EC_GROUP *EC_GROUP_new_by_curve_name(int nid);
116 
117 // EC_GROUP_free releases a reference to |group|.
118 OPENSSL_EXPORT void EC_GROUP_free(EC_GROUP *group);
119 
120 // EC_GROUP_dup takes a reference to |a| and returns it.
121 OPENSSL_EXPORT EC_GROUP *EC_GROUP_dup(const EC_GROUP *a);
122 
123 // EC_GROUP_cmp returns zero if |a| and |b| are the same group and non-zero
124 // otherwise.
125 OPENSSL_EXPORT int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b,
126                                 BN_CTX *ignored);
127 
128 // EC_GROUP_get0_generator returns a pointer to the internal |EC_POINT| object
129 // in |group| that specifies the generator for the group.
130 OPENSSL_EXPORT const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group);
131 
132 // EC_GROUP_get0_order returns a pointer to the internal |BIGNUM| object in
133 // |group| that specifies the order of the group.
134 OPENSSL_EXPORT const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group);
135 
136 // EC_GROUP_order_bits returns the number of bits of the order of |group|.
137 OPENSSL_EXPORT int EC_GROUP_order_bits(const EC_GROUP *group);
138 
139 // EC_GROUP_get_cofactor sets |*cofactor| to the cofactor of |group| using
140 // |ctx|, if it's not NULL. It returns one on success and zero otherwise.
141 OPENSSL_EXPORT int EC_GROUP_get_cofactor(const EC_GROUP *group,
142                                          BIGNUM *cofactor, BN_CTX *ctx);
143 
144 // EC_GROUP_get_curve_GFp gets various parameters about a group. It sets
145 // |*out_p| to the order of the coordinate field and |*out_a| and |*out_b| to
146 // the parameters of the curve when expressed as y² = x³ + ax + b. Any of the
147 // output parameters can be NULL. It returns one on success and zero on
148 // error.
149 OPENSSL_EXPORT int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *out_p,
150                                           BIGNUM *out_a, BIGNUM *out_b,
151                                           BN_CTX *ctx);
152 
153 // EC_GROUP_get_curve_name returns a NID that identifies |group|.
154 OPENSSL_EXPORT int EC_GROUP_get_curve_name(const EC_GROUP *group);
155 
156 // EC_GROUP_get_degree returns the number of bits needed to represent an
157 // element of the field underlying |group|.
158 OPENSSL_EXPORT unsigned EC_GROUP_get_degree(const EC_GROUP *group);
159 
160 // EC_curve_nid2nist returns the NIST name of the elliptic curve specified by
161 // |nid|, or NULL if |nid| is not a NIST curve. For example, it returns "P-256"
162 // for |NID_X9_62_prime256v1|.
163 OPENSSL_EXPORT const char *EC_curve_nid2nist(int nid);
164 
165 // EC_curve_nist2nid returns the NID of the elliptic curve specified by the NIST
166 // name |name|, or |NID_undef| if |name| is not a recognized name. For example,
167 // it returns |NID_X9_62_prime256v1| for "P-256".
168 OPENSSL_EXPORT int EC_curve_nist2nid(const char *name);
169 
170 
171 // Points on elliptic curves.
172 
173 // EC_POINT_new returns a fresh |EC_POINT| object in the given group, or NULL
174 // on error.
175 OPENSSL_EXPORT EC_POINT *EC_POINT_new(const EC_GROUP *group);
176 
177 // EC_POINT_free frees |point| and the data that it points to.
178 OPENSSL_EXPORT void EC_POINT_free(EC_POINT *point);
179 
180 // EC_POINT_copy sets |*dest| equal to |*src|. It returns one on success and
181 // zero otherwise.
182 OPENSSL_EXPORT int EC_POINT_copy(EC_POINT *dest, const EC_POINT *src);
183 
184 // EC_POINT_dup returns a fresh |EC_POINT| that contains the same values as
185 // |src|, or NULL on error.
186 OPENSSL_EXPORT EC_POINT *EC_POINT_dup(const EC_POINT *src,
187                                       const EC_GROUP *group);
188 
189 // EC_POINT_set_to_infinity sets |point| to be the "point at infinity" for the
190 // given group.
191 OPENSSL_EXPORT int EC_POINT_set_to_infinity(const EC_GROUP *group,
192                                             EC_POINT *point);
193 
194 // EC_POINT_is_at_infinity returns one iff |point| is the point at infinity and
195 // zero otherwise.
196 OPENSSL_EXPORT int EC_POINT_is_at_infinity(const EC_GROUP *group,
197                                            const EC_POINT *point);
198 
199 // EC_POINT_is_on_curve returns one if |point| is an element of |group| and
200 // and zero otherwise or when an error occurs. This is different from OpenSSL,
201 // which returns -1 on error. If |ctx| is non-NULL, it may be used.
202 OPENSSL_EXPORT int EC_POINT_is_on_curve(const EC_GROUP *group,
203                                         const EC_POINT *point, BN_CTX *ctx);
204 
205 // EC_POINT_cmp returns zero if |a| is equal to |b|, greater than zero if
206 // not equal and -1 on error. If |ctx| is not NULL, it may be used.
207 OPENSSL_EXPORT int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a,
208                                 const EC_POINT *b, BN_CTX *ctx);
209 
210 
211 // Point conversion.
212 
213 // EC_POINT_get_affine_coordinates_GFp sets |x| and |y| to the affine value of
214 // |point| using |ctx|, if it's not NULL. It returns one on success and zero
215 // otherwise.
216 //
217 // Either |x| or |y| may be NULL to skip computing that coordinate. This is
218 // slightly faster in the common case where only the x-coordinate is needed.
219 OPENSSL_EXPORT int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
220                                                        const EC_POINT *point,
221                                                        BIGNUM *x, BIGNUM *y,
222                                                        BN_CTX *ctx);
223 
224 // EC_POINT_set_affine_coordinates_GFp sets the value of |point| to be
225 // (|x|, |y|). The |ctx| argument may be used if not NULL. It returns one
226 // on success or zero on error. Note that, unlike with OpenSSL, it's
227 // considered an error if the point is not on the curve.
228 OPENSSL_EXPORT int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group,
229                                                        EC_POINT *point,
230                                                        const BIGNUM *x,
231                                                        const BIGNUM *y,
232                                                        BN_CTX *ctx);
233 
234 // EC_POINT_point2oct serialises |point| into the X9.62 form given by |form|
235 // into, at most, |len| bytes at |buf|. It returns the number of bytes written
236 // or zero on error if |buf| is non-NULL, else the number of bytes needed. The
237 // |ctx| argument may be used if not NULL.
238 OPENSSL_EXPORT size_t EC_POINT_point2oct(const EC_GROUP *group,
239                                          const EC_POINT *point,
240                                          point_conversion_form_t form,
241                                          uint8_t *buf, size_t len, BN_CTX *ctx);
242 
243 // EC_POINT_point2cbb behaves like |EC_POINT_point2oct| but appends the
244 // serialised point to |cbb|. It returns one on success and zero on error.
245 OPENSSL_EXPORT int EC_POINT_point2cbb(CBB *out, const EC_GROUP *group,
246                                       const EC_POINT *point,
247                                       point_conversion_form_t form,
248                                       BN_CTX *ctx);
249 
250 // EC_POINT_oct2point sets |point| from |len| bytes of X9.62 format
251 // serialisation in |buf|. It returns one on success and zero otherwise. The
252 // |ctx| argument may be used if not NULL.
253 OPENSSL_EXPORT int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *point,
254                                       const uint8_t *buf, size_t len,
255                                       BN_CTX *ctx);
256 
257 // EC_POINT_set_compressed_coordinates_GFp sets |point| to equal the point with
258 // the given |x| coordinate and the y coordinate specified by |y_bit| (see
259 // X9.62). It returns one on success and zero otherwise.
260 OPENSSL_EXPORT int EC_POINT_set_compressed_coordinates_GFp(
261     const EC_GROUP *group, EC_POINT *point, const BIGNUM *x, int y_bit,
262     BN_CTX *ctx);
263 
264 
265 // Group operations.
266 
267 // EC_POINT_add sets |r| equal to |a| plus |b|. It returns one on success and
268 // zero otherwise. If |ctx| is not NULL, it may be used.
269 OPENSSL_EXPORT int EC_POINT_add(const EC_GROUP *group, EC_POINT *r,
270                                 const EC_POINT *a, const EC_POINT *b,
271                                 BN_CTX *ctx);
272 
273 // EC_POINT_dbl sets |r| equal to |a| plus |a|. It returns one on success and
274 // zero otherwise. If |ctx| is not NULL, it may be used.
275 OPENSSL_EXPORT int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r,
276                                 const EC_POINT *a, BN_CTX *ctx);
277 
278 // EC_POINT_invert sets |a| equal to minus |a|. It returns one on success and
279 // zero otherwise. If |ctx| is not NULL, it may be used.
280 OPENSSL_EXPORT int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a,
281                                    BN_CTX *ctx);
282 
283 // EC_POINT_mul sets r = generator*n + q*m. It returns one on success and zero
284 // otherwise. If |ctx| is not NULL, it may be used.
285 OPENSSL_EXPORT int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r,
286                                 const BIGNUM *n, const EC_POINT *q,
287                                 const BIGNUM *m, BN_CTX *ctx);
288 
289 
290 // Deprecated functions.
291 
292 // EC_GROUP_new_curve_GFp creates a new, arbitrary elliptic curve group based
293 // on the equation y² = x³ + a·x + b. It returns the new group or NULL on
294 // error.
295 //
296 // This new group has no generator. It is an error to use a generator-less group
297 // with any functions except for |EC_GROUP_free|, |EC_POINT_new|,
298 // |EC_POINT_set_affine_coordinates_GFp|, and |EC_GROUP_set_generator|.
299 //
300 // |EC_GROUP|s returned by this function will always compare as unequal via
301 // |EC_GROUP_cmp| (even to themselves). |EC_GROUP_get_curve_name| will always
302 // return |NID_undef|.
303 //
304 // Avoid using arbitrary curves and use |EC_GROUP_new_by_curve_name| instead.
305 OPENSSL_EXPORT EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p,
306                                                 const BIGNUM *a,
307                                                 const BIGNUM *b, BN_CTX *ctx);
308 
309 // EC_GROUP_set_generator sets the generator for |group| to |generator|, which
310 // must have the given order and cofactor. It may only be used with |EC_GROUP|
311 // objects returned by |EC_GROUP_new_curve_GFp| and may only be used once on
312 // each group. |generator| must have been created using |group|.
313 OPENSSL_EXPORT int EC_GROUP_set_generator(EC_GROUP *group,
314                                           const EC_POINT *generator,
315                                           const BIGNUM *order,
316                                           const BIGNUM *cofactor);
317 
318 // EC_GROUP_get_order sets |*order| to the order of |group|, if it's not
319 // NULL. It returns one on success and zero otherwise. |ctx| is ignored. Use
320 // |EC_GROUP_get0_order| instead.
321 OPENSSL_EXPORT int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order,
322                                       BN_CTX *ctx);
323 
324 // EC_GROUP_set_asn1_flag does nothing.
325 OPENSSL_EXPORT void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag);
326 
327 #define OPENSSL_EC_NAMED_CURVE 0
328 #define OPENSSL_EC_EXPLICIT_CURVE 1
329 
330 typedef struct ec_method_st EC_METHOD;
331 
332 // EC_GROUP_method_of returns a dummy non-NULL pointer.
333 OPENSSL_EXPORT const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group);
334 
335 // EC_METHOD_get_field_type returns NID_X9_62_prime_field.
336 OPENSSL_EXPORT int EC_METHOD_get_field_type(const EC_METHOD *meth);
337 
338 // EC_GROUP_set_point_conversion_form aborts the process if |form| is not
339 // |POINT_CONVERSION_UNCOMPRESSED| and otherwise does nothing.
340 OPENSSL_EXPORT void EC_GROUP_set_point_conversion_form(
341     EC_GROUP *group, point_conversion_form_t form);
342 
343 // EC_builtin_curve describes a supported elliptic curve.
344 typedef struct {
345   int nid;
346   const char *comment;
347 } EC_builtin_curve;
348 
349 // EC_get_builtin_curves writes at most |max_num_curves| elements to
350 // |out_curves| and returns the total number that it would have written, had
351 // |max_num_curves| been large enough.
352 //
353 // The |EC_builtin_curve| items describe the supported elliptic curves.
354 OPENSSL_EXPORT size_t EC_get_builtin_curves(EC_builtin_curve *out_curves,
355                                             size_t max_num_curves);
356 
357 // EC_POINT_clear_free calls |EC_POINT_free|.
358 OPENSSL_EXPORT void EC_POINT_clear_free(EC_POINT *point);
359 
360 
361 #if defined(__cplusplus)
362 }  // extern C
363 #endif
364 
365 // Old code expects to get EC_KEY from ec.h.
366 #include <openssl/ec_key.h>
367 
368 #if defined(__cplusplus)
369 extern "C++" {
370 
371 BSSL_NAMESPACE_BEGIN
372 
373 BORINGSSL_MAKE_DELETER(EC_POINT, EC_POINT_free)
374 BORINGSSL_MAKE_DELETER(EC_GROUP, EC_GROUP_free)
375 
376 BSSL_NAMESPACE_END
377 
378 }  // extern C++
379 
380 #endif
381 
382 #define EC_R_BUFFER_TOO_SMALL 100
383 #define EC_R_COORDINATES_OUT_OF_RANGE 101
384 #define EC_R_D2I_ECPKPARAMETERS_FAILURE 102
385 #define EC_R_EC_GROUP_NEW_BY_NAME_FAILURE 103
386 #define EC_R_GROUP2PKPARAMETERS_FAILURE 104
387 #define EC_R_I2D_ECPKPARAMETERS_FAILURE 105
388 #define EC_R_INCOMPATIBLE_OBJECTS 106
389 #define EC_R_INVALID_COMPRESSED_POINT 107
390 #define EC_R_INVALID_COMPRESSION_BIT 108
391 #define EC_R_INVALID_ENCODING 109
392 #define EC_R_INVALID_FIELD 110
393 #define EC_R_INVALID_FORM 111
394 #define EC_R_INVALID_GROUP_ORDER 112
395 #define EC_R_INVALID_PRIVATE_KEY 113
396 #define EC_R_MISSING_PARAMETERS 114
397 #define EC_R_MISSING_PRIVATE_KEY 115
398 #define EC_R_NON_NAMED_CURVE 116
399 #define EC_R_NOT_INITIALIZED 117
400 #define EC_R_PKPARAMETERS2GROUP_FAILURE 118
401 #define EC_R_POINT_AT_INFINITY 119
402 #define EC_R_POINT_IS_NOT_ON_CURVE 120
403 #define EC_R_SLOT_FULL 121
404 #define EC_R_UNDEFINED_GENERATOR 122
405 #define EC_R_UNKNOWN_GROUP 123
406 #define EC_R_UNKNOWN_ORDER 124
407 #define EC_R_WRONG_ORDER 125
408 #define EC_R_BIGNUM_OUT_OF_RANGE 126
409 #define EC_R_WRONG_CURVE_PARAMETERS 127
410 #define EC_R_DECODE_ERROR 128
411 #define EC_R_ENCODE_ERROR 129
412 #define EC_R_GROUP_MISMATCH 130
413 #define EC_R_INVALID_COFACTOR 131
414 #define EC_R_PUBLIC_KEY_VALIDATION_FAILED 132
415 #define EC_R_INVALID_SCALAR 133
416 
417 #endif  // OPENSSL_HEADER_EC_H
418