b0ab12e6 |
1 | /* -*-c-*- |
2 | * |
b817bfc6 |
3 | * $Id: ec.h,v 1.11 2004/04/08 01:36:15 mdw Exp $ |
b0ab12e6 |
4 | * |
5 | * Elliptic curve definitions |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
b0ab12e6 |
30 | #ifndef CATACOMB_EC_H |
31 | #define CATACOMB_EC_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
432c4e18 |
39 | #ifndef CATACOMB_FIELD_H |
40 | # include "field.h" |
41 | #endif |
42 | |
43 | #ifndef CATACOMB_MP_H |
44 | # include "mp.h" |
45 | #endif |
46 | |
47 | #ifndef CATACOMB_QDPARSE_H |
48 | # include "qdparse.h" |
49 | #endif |
b0ab12e6 |
50 | |
51 | /*----- Data structures ---------------------------------------------------*/ |
52 | |
b085fd91 |
53 | /* --- An elliptic curve representation --- */ |
54 | |
b0ab12e6 |
55 | typedef struct ec_curve { |
56 | const struct ec_ops *ops; /* Curve operations */ |
57 | field *f; /* Underlying field structure */ |
432c4e18 |
58 | mp *a, *b; /* Standard params (internal form) */ |
b0ab12e6 |
59 | } ec_curve; |
60 | |
b085fd91 |
61 | /* --- An elliptic curve point --- */ |
62 | |
b0ab12e6 |
63 | typedef struct ec { |
64 | mp *x, *y; /* Point coordinates */ |
65 | mp *z; /* Common denominator (or null) */ |
66 | } ec; |
67 | |
b085fd91 |
68 | /* --- A factor for simultaneous multiplication --- */ |
69 | |
70 | typedef struct ec_mulfactor { |
71 | ec base; /* The point */ |
41cb1beb |
72 | mp *exp; /* The exponent */ |
b085fd91 |
73 | } ec_mulfactor; |
74 | |
8823192f |
75 | /* --- Elliptic curve operations --- * |
76 | * |
77 | * All operations (apart from @destroy@ and @in@) are guaranteed to be |
391faf42 |
78 | * performed on internal representations of points. |
79 | * |
80 | * (Historical note. We used to guarantee that the second to @add@ and @mul@ |
81 | * was the output of @in@ or @fix@, but this canonification turned out to |
82 | * make the precomputation in @ec_exp@ too slow. Projective implementations |
83 | * must therefore cope with a pair of arbitrary points.) |
8823192f |
84 | */ |
b085fd91 |
85 | |
b0ab12e6 |
86 | typedef struct ec_ops { |
87 | void (*destroy)(ec_curve */*c*/); |
34e4f738 |
88 | int (*samep)(ec_curve */*c*/, ec_curve */*d*/); |
41a324a7 |
89 | ec *(*in)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
90 | ec *(*out)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
91 | ec *(*fix)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
92 | ec *(*find)(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
b085fd91 |
93 | ec *(*neg)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
94 | ec *(*add)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
b085fd91 |
95 | ec *(*sub)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
41a324a7 |
96 | ec *(*dbl)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
97 | int (*check)(ec_curve */*c*/, const ec */*p*/); |
b0ab12e6 |
98 | } ec_ops; |
99 | |
34e4f738 |
100 | #define EC_SAMEP(c, d) (c)->ops->samep((c), (d)) |
41a324a7 |
101 | #define EC_IN(c, d, p) (c)->ops->in((c), (d), (p)) |
dbfee00a |
102 | #define EC_OUT(c, d, p) (c)->ops->out((c), (d), (p)) |
8823192f |
103 | #define EC_FIX(c, d, p) (c)->ops->fix((c), (d), (p)) |
41a324a7 |
104 | |
b0ab12e6 |
105 | #define EC_FIND(c, d, x) (c)->ops->find((c), (d), (x)) |
b085fd91 |
106 | #define EC_NEG(c, d, x) (c)->ops->neg((c), (d), (x)) |
b0ab12e6 |
107 | #define EC_ADD(c, d, p, q) (c)->ops->add((c), (d), (p), (q)) |
b085fd91 |
108 | #define EC_SUB(c, d, p, q) (c)->ops->sub((c), (d), (p), (q)) |
b0ab12e6 |
109 | #define EC_DBL(c, d, p) (c)->ops->dbl((c), (d), (p)) |
8823192f |
110 | #define EC_CHECK(c, p) (c)->ops->check((c), (p)) |
b0ab12e6 |
111 | |
432c4e18 |
112 | /* --- Elliptic curve parameters --- */ |
113 | |
114 | typedef struct ec_info { |
115 | ec_curve *c; /* The actual curve */ |
116 | ec g; /* The common point */ |
117 | mp *r; /* Order of %$g$% */ |
118 | mp *h; /* Cofactor %$h = \#E/r$% */ |
119 | } ec_info; |
120 | |
b0ab12e6 |
121 | /*----- Simple memory management things -----------------------------------*/ |
122 | |
123 | /* --- @ec_create@ --- * |
124 | * |
125 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
126 | * |
41a324a7 |
127 | * Returns: The argument @p@. |
b0ab12e6 |
128 | * |
129 | * Use: Initializes a new point. The initial value is the additive |
130 | * identity (which is universal for all curves). |
131 | */ |
132 | |
133 | #define EC_INIT { MP_NEW, MP_NEW, MP_NEW } |
134 | |
135 | #define EC_CREATE(p) do { \ |
136 | ec *_p = (p); \ |
137 | _p->x = _p->y = _p->z = MP_NEW; \ |
138 | } while (0) |
139 | |
41a324a7 |
140 | extern ec *ec_create(ec */*p*/); |
b0ab12e6 |
141 | |
142 | /* --- @ec_destroy@ --- * |
143 | * |
144 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
145 | * |
146 | * Returns: --- |
147 | * |
148 | * Use: Destroys a point, making it invalid. |
149 | */ |
150 | |
151 | #define EC_DESTROY(p) do { \ |
152 | ec *_p = (p); \ |
153 | if (!EC_ATINF(_p)) { \ |
154 | MP_DROP(_p->x); \ |
155 | MP_DROP(_p->y); \ |
156 | if (_p->z) MP_DROP(_p->z); \ |
157 | } \ |
158 | } while (0) |
159 | |
160 | extern void ec_destroy(ec */*p*/); |
161 | |
162 | /* --- @ec_atinf@ --- * |
163 | * |
164 | * Arguments: @const ec *p@ = pointer to a point |
165 | * |
166 | * Returns: Nonzero if %$p = O$% is the point at infinity, zero |
167 | * otherwise. |
168 | */ |
169 | |
170 | #define EC_ATINF(p) ((p)->x == MP_NEW || (p)->x == MP_NEWSEC) |
171 | |
172 | extern int ec_atinf(const ec */*p*/); |
173 | |
174 | /* --- @ec_setinf@ --- * |
175 | * |
176 | * Arguments: @ec *p@ = pointer to a point |
177 | * |
41a324a7 |
178 | * Returns: The argument @p@. |
b0ab12e6 |
179 | * |
180 | * Use: Sets the given point to be the point %$O$% at infinity. |
181 | */ |
182 | |
183 | #define EC_SETINF(p) do { \ |
184 | ec *_p = (p); \ |
185 | if (!EC_ATINF(_p)) { \ |
186 | MP_DROP(_p->x); \ |
187 | MP_DROP(_p->y); \ |
188 | if (_p->z) MP_DROP(_p->z); \ |
189 | _p->x = _p->y = _p->z = MP_NEW; \ |
190 | _p->y = MP_NEW; \ |
191 | _p->z = MP_NEW; \ |
192 | } \ |
193 | } while (0) |
194 | |
41a324a7 |
195 | extern ec *ec_setinf(ec */*p*/); |
b0ab12e6 |
196 | |
197 | /* --- @ec_copy@ --- * |
198 | * |
199 | * Arguments: @ec *d@ = pointer to destination point |
200 | * @const ec *p@ = pointer to source point |
201 | * |
41a324a7 |
202 | * Returns: The destination @d@. |
b0ab12e6 |
203 | * |
204 | * Use: Creates a copy of an elliptic curve point. |
205 | */ |
206 | |
207 | #define EC_COPY(d, p) do { \ |
208 | ec *_d = (d); \ |
209 | const ec *_p = (p); \ |
210 | if (d != p) { \ |
211 | EC_DESTROY(d); \ |
212 | if (EC_ATINF(p)) \ |
213 | _d->x = _d->y = _d->z = MP_NEW; \ |
214 | else { \ |
b085fd91 |
215 | _d->x = MP_COPY(_p->x); \ |
216 | _d->y = MP_COPY(_p->y); \ |
217 | _d->z = _p->z ? MP_COPY(_p->z) : MP_NEW; \ |
b0ab12e6 |
218 | } \ |
219 | } \ |
220 | } while (0) |
221 | |
41a324a7 |
222 | extern ec *ec_copy(ec */*d*/, const ec */*p*/); |
b0ab12e6 |
223 | |
bc985cef |
224 | /* --- @ec_eq@ --- * |
225 | * |
226 | * Arguments: @const ec *p, *q@ = two points |
227 | * |
228 | * Returns: Nonzero if the points are equal. Compares external-format |
229 | * points. |
230 | */ |
231 | |
232 | #define EC_EQ(p, q) \ |
233 | ((EC_ATINF(p) && EC_ATINF(q)) || \ |
234 | (!EC_ATINF(p) && !EC_ATINF(q) && \ |
235 | MP_EQ((p)->x, (q)->x) && \ |
236 | MP_EQ((p)->y, (q)->y))) |
237 | |
238 | extern int ec_eq(const ec *p, const ec *q); |
239 | |
b0ab12e6 |
240 | /*----- Interesting arithmetic --------------------------------------------*/ |
241 | |
34e4f738 |
242 | /* --- @ec_samep@ --- * |
243 | * |
244 | * Arguments: @ec_curve *c, *d@ = two elliptic curves |
245 | * |
246 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
247 | * |
248 | * Use: Checks for sameness of curves. This function does the full |
249 | * check, not just the curve-type-specific check done by the |
250 | * @sampep@ field operation. |
251 | */ |
252 | |
253 | extern int ec_samep(ec_curve */*c*/, ec_curve */*d*/); |
254 | |
b0ab12e6 |
255 | /* --- @ec_find@ --- * |
256 | * |
257 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
258 | * @ec *d@ = pointer to the destination point |
259 | * @mp *x@ = a possible x-coordinate |
260 | * |
b085fd91 |
261 | * Returns: The destination if OK, or null if no point was found. |
b0ab12e6 |
262 | * |
b085fd91 |
263 | * Use: Finds a point on an elliptic curve with a given |
264 | * x-coordinate. If there is no point with the given |
265 | * %$x$%-coordinate, a null pointer is returned and the |
266 | * destination is left invalid. |
b0ab12e6 |
267 | */ |
268 | |
b085fd91 |
269 | extern ec *ec_find(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
270 | |
bc985cef |
271 | /* --- @ec_rand@ --- * |
272 | * |
273 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
274 | * @ec *d@ = pointer to the destination point |
275 | * @grand *r@ = random number source |
276 | * |
277 | * Returns: The destination @d@. |
278 | * |
279 | * Use: Finds a random point on the given curve. |
280 | */ |
281 | |
282 | extern ec *ec_rand(ec_curve */*c*/, ec */*d*/, grand */*r*/); |
283 | |
b085fd91 |
284 | /* --- @ec_neg@ --- * |
285 | * |
286 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
287 | * @ec *d@ = pointer to the destination point |
288 | * @const ec *p@ = pointer to the operand point |
289 | * |
290 | * Returns: The destination point. |
291 | * |
292 | * Use: Computes the negation of the given point. |
293 | */ |
294 | |
295 | extern ec *ec_neg(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
296 | |
297 | /* --- @ec_add@ --- * |
298 | * |
299 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
300 | * @ec *d@ = pointer to the destination point |
301 | * @const ec *p, *q@ = pointers to the operand points |
302 | * |
41a324a7 |
303 | * Returns: The destination @d@. |
b0ab12e6 |
304 | * |
305 | * Use: Adds two points on an elliptic curve. |
306 | */ |
307 | |
41a324a7 |
308 | extern ec *ec_add(ec_curve */*c*/, ec */*d*/, |
309 | const ec */*p*/, const ec */*q*/); |
b0ab12e6 |
310 | |
b085fd91 |
311 | /* --- @ec_sub@ --- * |
312 | * |
313 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
314 | * @ec *d@ = pointer to the destination point |
315 | * @const ec *p, *q@ = pointers to the operand points |
316 | * |
317 | * Returns: The destination @d@. |
318 | * |
319 | * Use: Subtracts one point from another on an elliptic curve. |
320 | */ |
321 | |
322 | extern ec *ec_sub(ec_curve */*c*/, ec */*d*/, |
323 | const ec */*p*/, const ec */*q*/); |
324 | |
b0ab12e6 |
325 | /* --- @ec_dbl@ --- * |
326 | * |
327 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
328 | * @ec *d@ = pointer to the destination point |
329 | * @const ec *p@ = pointer to the operand point |
330 | * |
41a324a7 |
331 | * Returns: The destination @d@. |
b0ab12e6 |
332 | * |
333 | * Use: Doubles a point on an elliptic curve. |
334 | */ |
335 | |
41a324a7 |
336 | extern ec *ec_dbl(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
337 | |
8823192f |
338 | /* --- @ec_check@ --- * |
339 | * |
340 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
341 | * @const ec *p@ = pointer to the point |
342 | * |
343 | * Returns: Zero if OK, nonzero if this is an invalid point. |
344 | * |
345 | * Use: Checks that a point is actually on an elliptic curve. |
346 | */ |
347 | |
348 | extern int ec_check(ec_curve */*c*/, const ec */*p*/); |
349 | |
b085fd91 |
350 | /* --- @ec_mul@, @ec_imul@ --- * |
b0ab12e6 |
351 | * |
352 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
353 | * @ec *d@ = pointer to the destination point |
354 | * @const ec *p@ = pointer to the generator point |
355 | * @mp *n@ = integer multiplier |
356 | * |
41a324a7 |
357 | * Returns: The destination @d@. |
b0ab12e6 |
358 | * |
b085fd91 |
359 | * Use: Multiplies a point by a scalar, returning %$n p$%. The |
360 | * @imul@ variant uses internal representations for argument |
361 | * and result. |
b0ab12e6 |
362 | */ |
363 | |
41a324a7 |
364 | extern ec *ec_mul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
b085fd91 |
365 | extern ec *ec_imul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
366 | |
367 | /* --- @ec_mmul@, @ec_immul@ --- * |
368 | * |
369 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
370 | * @ec *d@ = pointer to the destination point |
371 | * @const ec_mulfactor *f@ = pointer to vector of factors |
372 | * @size_t n@ = number of factors |
373 | * |
374 | * Returns: The destination @d@. |
375 | * |
376 | * Use: Does simultaneous point multiplication. The @immul@ variant |
377 | * uses internal representations for arguments and result. |
378 | */ |
379 | |
380 | extern ec *ec_mmul(ec_curve */*c*/, ec */*d*/, |
381 | const ec_mulfactor */*f*/, size_t /*n*/); |
382 | extern ec *ec_immul(ec_curve */*c*/, ec */*d*/, |
383 | const ec_mulfactor */*f*/, size_t /*n*/); |
41a324a7 |
384 | |
385 | /*----- Standard curve operations -----------------------------------------*/ |
386 | |
34e4f738 |
387 | /* --- @ec_stdsamep@ --- * |
388 | * |
389 | * Arguments: @ec_curve *c, *d@ = two elliptic curves |
390 | * |
391 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
392 | * |
393 | * Use: Simple sameness check on @a@ and @b@ curve members. |
394 | */ |
395 | |
396 | extern int ec_stdsamep(ec_curve */*c*/, ec_curve */*d*/); |
397 | |
8823192f |
398 | /* --- @ec_idin@, @ec_idout@, @ec_idfix@ --- * |
41a324a7 |
399 | * |
400 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
401 | * @ec *d@ = pointer to the destination |
402 | * @const ec *p@ = pointer to a source point |
403 | * |
404 | * Returns: The destination @d@. |
405 | * |
406 | * Use: An identity operation if your curve has no internal |
407 | * representation. (The field internal representation is still |
408 | * used.) |
409 | */ |
410 | |
411 | extern ec *ec_idin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
412 | extern ec *ec_idout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
413 | extern ec *ec_idfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
414 | |
8823192f |
415 | /* --- @ec_projin@, @ec_projout@, @ec_projfix@ --- * |
41a324a7 |
416 | * |
417 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
418 | * @ec *d@ = pointer to the destination |
419 | * @const ec *p@ = pointer to a source point |
420 | * |
421 | * Returns: The destination @d@. |
422 | * |
423 | * Use: Conversion functions if your curve operations use a |
424 | * projective representation. |
425 | */ |
426 | |
427 | extern ec *ec_projin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
428 | extern ec *ec_projout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
429 | extern ec *ec_projfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
430 | |
b085fd91 |
431 | /* --- @ec_stdsub@ --- * |
432 | * |
433 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
434 | * @ec *d@ = pointer to the destination |
41cb1beb |
435 | * @const ec *p, *q@ = the operand points |
b085fd91 |
436 | * |
437 | * Returns: The destination @d@. |
438 | * |
439 | * Use: Standard point subtraction operation, in terms of negation |
440 | * and addition. This isn't as efficient as a ready-made |
441 | * subtraction operator. |
442 | */ |
443 | |
41cb1beb |
444 | extern ec *ec_stdsub(ec_curve */*c*/, ec */*d*/, |
445 | const ec */*p*/, const ec */*q*/); |
b085fd91 |
446 | |
b0ab12e6 |
447 | /*----- Creating curves ---------------------------------------------------*/ |
448 | |
b085fd91 |
449 | /* --- @ec_destroycurve@ --- * |
450 | * |
451 | * Arguments: @ec_curve *c@ = pointer to an ellptic curve |
452 | * |
453 | * Returns: --- |
454 | * |
455 | * Use: Destroys a description of an elliptic curve. |
456 | */ |
457 | |
458 | extern void ec_destroycurve(ec_curve */*c*/); |
459 | |
460 | /* --- @ec_prime@, @ec_primeproj@ --- * |
b0ab12e6 |
461 | * |
dbfee00a |
462 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
b0ab12e6 |
463 | * @mp *a, *b@ = the coefficients for this curve |
464 | * |
02d7884d |
465 | * Returns: A pointer to the curve, or null. |
b0ab12e6 |
466 | * |
467 | * Use: Creates a curve structure for an elliptic curve defined over |
b085fd91 |
468 | * a prime field. The @primeproj@ variant uses projective |
469 | * coordinates, which can be a win. |
b0ab12e6 |
470 | */ |
471 | |
472 | extern ec_curve *ec_prime(field */*f*/, mp */*a*/, mp */*b*/); |
b085fd91 |
473 | extern ec_curve *ec_primeproj(field */*f*/, mp */*a*/, mp */*b*/); |
b0ab12e6 |
474 | |
ceb3f0c0 |
475 | /* --- @ec_bin@, @ec_binproj@ --- * |
b0ab12e6 |
476 | * |
477 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
478 | * @mp *a, *b@ = the coefficients for this curve |
479 | * |
02d7884d |
480 | * Returns: A pointer to the curve, or null. |
b0ab12e6 |
481 | * |
ceb3f0c0 |
482 | * Use: Creates a curve structure for an elliptic curve defined over |
483 | * a binary field. The @binproj@ variant uses projective |
484 | * coordinates, which can be a win. |
b0ab12e6 |
485 | */ |
486 | |
487 | extern ec_curve *ec_bin(field */*f*/, mp */*a*/, mp */*b*/); |
ceb3f0c0 |
488 | extern ec_curve *ec_binproj(field */*f*/, mp */*a*/, mp */*b*/); |
b0ab12e6 |
489 | |
432c4e18 |
490 | /*----- Curve parameter sets ----------------------------------------------*/ |
491 | |
492 | /* --- @ec_curveparse@ --- * |
493 | * |
494 | * Arguments: @qd_parse *qd@ = parser context |
495 | * |
496 | * Returns: Elliptic curve pointer if OK, or null. |
497 | * |
498 | * Use: Parses an elliptic curve description, which has the form |
499 | * |
500 | * * a field description |
501 | * * an optional `/' |
502 | * * `prime', `primeproj', `bin', or `binproj' |
503 | * * an optional `:' |
504 | * * the %$a$% parameter |
505 | * * an optional `,' |
506 | * * the %$b$% parameter |
507 | */ |
508 | |
509 | extern ec_curve *ec_curveparse(qd_parse */*qd*/); |
510 | |
511 | /* --- @ec_ptparse@ --- * |
512 | * |
513 | * Arguments: @qd_parse *qd@ = parser context |
514 | * @ec *p@ = where to put the point |
515 | * |
516 | * Returns: The point address, or null. |
517 | * |
518 | * Use: Parses an elliptic curve point. This has the form |
519 | * |
520 | * * %$x$%-coordinate |
521 | * * optional `,' |
522 | * * %$y$%-coordinate |
523 | */ |
524 | |
525 | extern ec *ec_ptparse(qd_parse */*qd*/, ec */*p*/); |
526 | |
527 | /* --- @ec_infoparse@ --- * |
528 | * |
529 | * Arguments: @qd_parse *qd@ = parser context |
530 | * @ec_info *ei@ = curve information block, currently |
531 | * uninitialized |
532 | * |
533 | * Returns: Zero on success, nonzero on failure. |
534 | * |
535 | * Use: Parses an elliptic curve information string, and stores the |
536 | * information in @ei@. This has the form |
537 | * |
538 | * * elliptic curve description |
539 | * * optional `/' |
540 | * * common point |
541 | * * optional `:' |
542 | * * group order |
543 | * * optional `*' |
544 | * * cofactor |
545 | */ |
546 | |
547 | extern int ec_infoparse(qd_parse */*qd*/, ec_info */*ei*/); |
548 | |
549 | /* --- @ec_getinfo@ --- * |
550 | * |
551 | * Arguments: @ec_info *ei@ = where to write the information |
552 | * @const char *p@ = string describing a curve |
553 | * |
554 | * Returns: Null on success, or a pointer to an error message. |
555 | * |
556 | * Use: Parses out information about a curve. The string is either a |
557 | * standard curve name, or a curve info string. |
558 | */ |
559 | |
560 | extern const char *ec_getinfo(ec_info */*ei*/, const char */*p*/); |
561 | |
34e4f738 |
562 | /* --- @ec_sameinfop@ --- * |
563 | * |
564 | * Arguments: @ec_info *ei, *ej@ = two elliptic curve parameter sets |
565 | * |
566 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
567 | * |
568 | * Use: Checks for sameness of curve parameters. |
569 | */ |
570 | |
571 | extern int ec_sameinfop(ec_info */*ei*/, ec_info */*ej*/); |
572 | |
432c4e18 |
573 | /* --- @ec_freeinfo@ --- * |
574 | * |
575 | * Arguments: @ec_info *ei@ = elliptic curve information block to free |
576 | * |
577 | * Returns: --- |
578 | * |
579 | * Use: Frees the information block. |
580 | */ |
581 | |
582 | extern void ec_freeinfo(ec_info */*ei*/); |
583 | |
584 | /* --- @ec_checkinfo@ --- * |
585 | * |
586 | * Arguments: @const ec_info *ei@ = elliptic curve information block |
587 | * |
588 | * Returns: Null if OK, or pointer to error message. |
589 | * |
590 | * Use: Checks an elliptic curve according to the rules in SEC1. |
591 | */ |
592 | |
593 | extern const char *ec_checkinfo(const ec_info */*ei*/, grand */*gr*/); |
594 | |
b0ab12e6 |
595 | /*----- That's all, folks -------------------------------------------------*/ |
596 | |
597 | #ifdef __cplusplus |
598 | } |
599 | #endif |
600 | |
601 | #endif |