b0ab12e6 |
1 | /* -*-c-*- |
2 | * |
432c4e18 |
3 | * $Id: ec.h,v 1.8 2004/03/27 17:54:11 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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: ec.h,v $ |
432c4e18 |
33 | * Revision 1.8 2004/03/27 17:54:11 mdw |
34 | * Standard curves and curve checking. |
35 | * |
bc985cef |
36 | * Revision 1.7 2004/03/23 15:19:32 mdw |
37 | * Test elliptic curves more thoroughly. |
38 | * |
391faf42 |
39 | * Revision 1.6 2004/03/22 02:19:10 mdw |
40 | * Rationalise the sliding-window threshold. Drop guarantee that right |
41 | * arguments to EC @add@ are canonical, and fix up projective implementations |
42 | * to cope. |
43 | * |
c3caa2fa |
44 | * Revision 1.5 2004/03/21 22:52:06 mdw |
45 | * Merge and close elliptic curve branch. |
46 | * |
ceb3f0c0 |
47 | * Revision 1.4.4.3 2004/03/21 22:39:46 mdw |
48 | * Elliptic curves on binary fields work. |
49 | * |
8823192f |
50 | * Revision 1.4.4.2 2004/03/20 00:13:31 mdw |
51 | * Projective coordinates for prime curves |
52 | * |
dbfee00a |
53 | * Revision 1.4.4.1 2003/06/10 13:43:53 mdw |
54 | * Simple (non-projective) curves over prime fields now seem to work. |
55 | * |
41cb1beb |
56 | * Revision 1.4 2003/05/15 23:25:59 mdw |
57 | * Make elliptic curve stuff build. |
58 | * |
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59 | * Revision 1.3 2002/01/13 13:48:44 mdw |
60 | * Further progress. |
61 | * |
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62 | * Revision 1.2 2001/05/07 17:29:44 mdw |
63 | * Treat projective coordinates as an internal representation. Various |
64 | * minor interface changes. |
65 | * |
b0ab12e6 |
66 | * Revision 1.1 2001/04/29 18:12:33 mdw |
67 | * Prototype version. |
68 | * |
69 | */ |
70 | |
71 | #ifndef CATACOMB_EC_H |
72 | #define CATACOMB_EC_H |
73 | |
74 | #ifdef __cplusplus |
75 | extern "C" { |
76 | #endif |
77 | |
78 | /*----- Header files ------------------------------------------------------*/ |
79 | |
432c4e18 |
80 | #ifndef CATACOMB_FIELD_H |
81 | # include "field.h" |
82 | #endif |
83 | |
84 | #ifndef CATACOMB_MP_H |
85 | # include "mp.h" |
86 | #endif |
87 | |
88 | #ifndef CATACOMB_QDPARSE_H |
89 | # include "qdparse.h" |
90 | #endif |
b0ab12e6 |
91 | |
92 | /*----- Data structures ---------------------------------------------------*/ |
93 | |
b085fd91 |
94 | /* --- An elliptic curve representation --- */ |
95 | |
b0ab12e6 |
96 | typedef struct ec_curve { |
97 | const struct ec_ops *ops; /* Curve operations */ |
98 | field *f; /* Underlying field structure */ |
432c4e18 |
99 | mp *a, *b; /* Standard params (internal form) */ |
b0ab12e6 |
100 | } ec_curve; |
101 | |
b085fd91 |
102 | /* --- An elliptic curve point --- */ |
103 | |
b0ab12e6 |
104 | typedef struct ec { |
105 | mp *x, *y; /* Point coordinates */ |
106 | mp *z; /* Common denominator (or null) */ |
107 | } ec; |
108 | |
b085fd91 |
109 | /* --- A factor for simultaneous multiplication --- */ |
110 | |
111 | typedef struct ec_mulfactor { |
112 | ec base; /* The point */ |
41cb1beb |
113 | mp *exp; /* The exponent */ |
b085fd91 |
114 | } ec_mulfactor; |
115 | |
8823192f |
116 | /* --- Elliptic curve operations --- * |
117 | * |
118 | * All operations (apart from @destroy@ and @in@) are guaranteed to be |
391faf42 |
119 | * performed on internal representations of points. |
120 | * |
121 | * (Historical note. We used to guarantee that the second to @add@ and @mul@ |
122 | * was the output of @in@ or @fix@, but this canonification turned out to |
123 | * make the precomputation in @ec_exp@ too slow. Projective implementations |
124 | * must therefore cope with a pair of arbitrary points.) |
8823192f |
125 | */ |
b085fd91 |
126 | |
b0ab12e6 |
127 | typedef struct ec_ops { |
128 | void (*destroy)(ec_curve */*c*/); |
41a324a7 |
129 | ec *(*in)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
130 | ec *(*out)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
131 | ec *(*fix)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
132 | ec *(*find)(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
b085fd91 |
133 | ec *(*neg)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
134 | ec *(*add)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
b085fd91 |
135 | ec *(*sub)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
41a324a7 |
136 | ec *(*dbl)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
137 | int (*check)(ec_curve */*c*/, const ec */*p*/); |
b0ab12e6 |
138 | } ec_ops; |
139 | |
41a324a7 |
140 | #define EC_IN(c, d, p) (c)->ops->in((c), (d), (p)) |
dbfee00a |
141 | #define EC_OUT(c, d, p) (c)->ops->out((c), (d), (p)) |
8823192f |
142 | #define EC_FIX(c, d, p) (c)->ops->fix((c), (d), (p)) |
41a324a7 |
143 | |
b0ab12e6 |
144 | #define EC_FIND(c, d, x) (c)->ops->find((c), (d), (x)) |
b085fd91 |
145 | #define EC_NEG(c, d, x) (c)->ops->neg((c), (d), (x)) |
b0ab12e6 |
146 | #define EC_ADD(c, d, p, q) (c)->ops->add((c), (d), (p), (q)) |
b085fd91 |
147 | #define EC_SUB(c, d, p, q) (c)->ops->sub((c), (d), (p), (q)) |
b0ab12e6 |
148 | #define EC_DBL(c, d, p) (c)->ops->dbl((c), (d), (p)) |
8823192f |
149 | #define EC_CHECK(c, p) (c)->ops->check((c), (p)) |
b0ab12e6 |
150 | |
432c4e18 |
151 | /* --- Elliptic curve parameters --- */ |
152 | |
153 | typedef struct ec_info { |
154 | ec_curve *c; /* The actual curve */ |
155 | ec g; /* The common point */ |
156 | mp *r; /* Order of %$g$% */ |
157 | mp *h; /* Cofactor %$h = \#E/r$% */ |
158 | } ec_info; |
159 | |
b0ab12e6 |
160 | /*----- Simple memory management things -----------------------------------*/ |
161 | |
162 | /* --- @ec_create@ --- * |
163 | * |
164 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
165 | * |
41a324a7 |
166 | * Returns: The argument @p@. |
b0ab12e6 |
167 | * |
168 | * Use: Initializes a new point. The initial value is the additive |
169 | * identity (which is universal for all curves). |
170 | */ |
171 | |
172 | #define EC_INIT { MP_NEW, MP_NEW, MP_NEW } |
173 | |
174 | #define EC_CREATE(p) do { \ |
175 | ec *_p = (p); \ |
176 | _p->x = _p->y = _p->z = MP_NEW; \ |
177 | } while (0) |
178 | |
41a324a7 |
179 | extern ec *ec_create(ec */*p*/); |
b0ab12e6 |
180 | |
181 | /* --- @ec_destroy@ --- * |
182 | * |
183 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
184 | * |
185 | * Returns: --- |
186 | * |
187 | * Use: Destroys a point, making it invalid. |
188 | */ |
189 | |
190 | #define EC_DESTROY(p) do { \ |
191 | ec *_p = (p); \ |
192 | if (!EC_ATINF(_p)) { \ |
193 | MP_DROP(_p->x); \ |
194 | MP_DROP(_p->y); \ |
195 | if (_p->z) MP_DROP(_p->z); \ |
196 | } \ |
197 | } while (0) |
198 | |
199 | extern void ec_destroy(ec */*p*/); |
200 | |
201 | /* --- @ec_atinf@ --- * |
202 | * |
203 | * Arguments: @const ec *p@ = pointer to a point |
204 | * |
205 | * Returns: Nonzero if %$p = O$% is the point at infinity, zero |
206 | * otherwise. |
207 | */ |
208 | |
209 | #define EC_ATINF(p) ((p)->x == MP_NEW || (p)->x == MP_NEWSEC) |
210 | |
211 | extern int ec_atinf(const ec */*p*/); |
212 | |
213 | /* --- @ec_setinf@ --- * |
214 | * |
215 | * Arguments: @ec *p@ = pointer to a point |
216 | * |
41a324a7 |
217 | * Returns: The argument @p@. |
b0ab12e6 |
218 | * |
219 | * Use: Sets the given point to be the point %$O$% at infinity. |
220 | */ |
221 | |
222 | #define EC_SETINF(p) do { \ |
223 | ec *_p = (p); \ |
224 | if (!EC_ATINF(_p)) { \ |
225 | MP_DROP(_p->x); \ |
226 | MP_DROP(_p->y); \ |
227 | if (_p->z) MP_DROP(_p->z); \ |
228 | _p->x = _p->y = _p->z = MP_NEW; \ |
229 | _p->y = MP_NEW; \ |
230 | _p->z = MP_NEW; \ |
231 | } \ |
232 | } while (0) |
233 | |
41a324a7 |
234 | extern ec *ec_setinf(ec */*p*/); |
b0ab12e6 |
235 | |
236 | /* --- @ec_copy@ --- * |
237 | * |
238 | * Arguments: @ec *d@ = pointer to destination point |
239 | * @const ec *p@ = pointer to source point |
240 | * |
41a324a7 |
241 | * Returns: The destination @d@. |
b0ab12e6 |
242 | * |
243 | * Use: Creates a copy of an elliptic curve point. |
244 | */ |
245 | |
246 | #define EC_COPY(d, p) do { \ |
247 | ec *_d = (d); \ |
248 | const ec *_p = (p); \ |
249 | if (d != p) { \ |
250 | EC_DESTROY(d); \ |
251 | if (EC_ATINF(p)) \ |
252 | _d->x = _d->y = _d->z = MP_NEW; \ |
253 | else { \ |
b085fd91 |
254 | _d->x = MP_COPY(_p->x); \ |
255 | _d->y = MP_COPY(_p->y); \ |
256 | _d->z = _p->z ? MP_COPY(_p->z) : MP_NEW; \ |
b0ab12e6 |
257 | } \ |
258 | } \ |
259 | } while (0) |
260 | |
41a324a7 |
261 | extern ec *ec_copy(ec */*d*/, const ec */*p*/); |
b0ab12e6 |
262 | |
bc985cef |
263 | /* --- @ec_eq@ --- * |
264 | * |
265 | * Arguments: @const ec *p, *q@ = two points |
266 | * |
267 | * Returns: Nonzero if the points are equal. Compares external-format |
268 | * points. |
269 | */ |
270 | |
271 | #define EC_EQ(p, q) \ |
272 | ((EC_ATINF(p) && EC_ATINF(q)) || \ |
273 | (!EC_ATINF(p) && !EC_ATINF(q) && \ |
274 | MP_EQ((p)->x, (q)->x) && \ |
275 | MP_EQ((p)->y, (q)->y))) |
276 | |
277 | extern int ec_eq(const ec *p, const ec *q); |
278 | |
b0ab12e6 |
279 | /*----- Interesting arithmetic --------------------------------------------*/ |
280 | |
b0ab12e6 |
281 | /* --- @ec_find@ --- * |
282 | * |
283 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
284 | * @ec *d@ = pointer to the destination point |
285 | * @mp *x@ = a possible x-coordinate |
286 | * |
b085fd91 |
287 | * Returns: The destination if OK, or null if no point was found. |
b0ab12e6 |
288 | * |
b085fd91 |
289 | * Use: Finds a point on an elliptic curve with a given |
290 | * x-coordinate. If there is no point with the given |
291 | * %$x$%-coordinate, a null pointer is returned and the |
292 | * destination is left invalid. |
b0ab12e6 |
293 | */ |
294 | |
b085fd91 |
295 | extern ec *ec_find(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
296 | |
bc985cef |
297 | /* --- @ec_rand@ --- * |
298 | * |
299 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
300 | * @ec *d@ = pointer to the destination point |
301 | * @grand *r@ = random number source |
302 | * |
303 | * Returns: The destination @d@. |
304 | * |
305 | * Use: Finds a random point on the given curve. |
306 | */ |
307 | |
308 | extern ec *ec_rand(ec_curve */*c*/, ec */*d*/, grand */*r*/); |
309 | |
b085fd91 |
310 | /* --- @ec_neg@ --- * |
311 | * |
312 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
313 | * @ec *d@ = pointer to the destination point |
314 | * @const ec *p@ = pointer to the operand point |
315 | * |
316 | * Returns: The destination point. |
317 | * |
318 | * Use: Computes the negation of the given point. |
319 | */ |
320 | |
321 | extern ec *ec_neg(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
322 | |
323 | /* --- @ec_add@ --- * |
324 | * |
325 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
326 | * @ec *d@ = pointer to the destination point |
327 | * @const ec *p, *q@ = pointers to the operand points |
328 | * |
41a324a7 |
329 | * Returns: The destination @d@. |
b0ab12e6 |
330 | * |
331 | * Use: Adds two points on an elliptic curve. |
332 | */ |
333 | |
41a324a7 |
334 | extern ec *ec_add(ec_curve */*c*/, ec */*d*/, |
335 | const ec */*p*/, const ec */*q*/); |
b0ab12e6 |
336 | |
b085fd91 |
337 | /* --- @ec_sub@ --- * |
338 | * |
339 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
340 | * @ec *d@ = pointer to the destination point |
341 | * @const ec *p, *q@ = pointers to the operand points |
342 | * |
343 | * Returns: The destination @d@. |
344 | * |
345 | * Use: Subtracts one point from another on an elliptic curve. |
346 | */ |
347 | |
348 | extern ec *ec_sub(ec_curve */*c*/, ec */*d*/, |
349 | const ec */*p*/, const ec */*q*/); |
350 | |
b0ab12e6 |
351 | /* --- @ec_dbl@ --- * |
352 | * |
353 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
354 | * @ec *d@ = pointer to the destination point |
355 | * @const ec *p@ = pointer to the operand point |
356 | * |
41a324a7 |
357 | * Returns: The destination @d@. |
b0ab12e6 |
358 | * |
359 | * Use: Doubles a point on an elliptic curve. |
360 | */ |
361 | |
41a324a7 |
362 | extern ec *ec_dbl(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
363 | |
8823192f |
364 | /* --- @ec_check@ --- * |
365 | * |
366 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
367 | * @const ec *p@ = pointer to the point |
368 | * |
369 | * Returns: Zero if OK, nonzero if this is an invalid point. |
370 | * |
371 | * Use: Checks that a point is actually on an elliptic curve. |
372 | */ |
373 | |
374 | extern int ec_check(ec_curve */*c*/, const ec */*p*/); |
375 | |
b085fd91 |
376 | /* --- @ec_mul@, @ec_imul@ --- * |
b0ab12e6 |
377 | * |
378 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
379 | * @ec *d@ = pointer to the destination point |
380 | * @const ec *p@ = pointer to the generator point |
381 | * @mp *n@ = integer multiplier |
382 | * |
41a324a7 |
383 | * Returns: The destination @d@. |
b0ab12e6 |
384 | * |
b085fd91 |
385 | * Use: Multiplies a point by a scalar, returning %$n p$%. The |
386 | * @imul@ variant uses internal representations for argument |
387 | * and result. |
b0ab12e6 |
388 | */ |
389 | |
41a324a7 |
390 | extern ec *ec_mul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
b085fd91 |
391 | extern ec *ec_imul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
392 | |
393 | /* --- @ec_mmul@, @ec_immul@ --- * |
394 | * |
395 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
396 | * @ec *d@ = pointer to the destination point |
397 | * @const ec_mulfactor *f@ = pointer to vector of factors |
398 | * @size_t n@ = number of factors |
399 | * |
400 | * Returns: The destination @d@. |
401 | * |
402 | * Use: Does simultaneous point multiplication. The @immul@ variant |
403 | * uses internal representations for arguments and result. |
404 | */ |
405 | |
406 | extern ec *ec_mmul(ec_curve */*c*/, ec */*d*/, |
407 | const ec_mulfactor */*f*/, size_t /*n*/); |
408 | extern ec *ec_immul(ec_curve */*c*/, ec */*d*/, |
409 | const ec_mulfactor */*f*/, size_t /*n*/); |
41a324a7 |
410 | |
411 | /*----- Standard curve operations -----------------------------------------*/ |
412 | |
8823192f |
413 | /* --- @ec_idin@, @ec_idout@, @ec_idfix@ --- * |
41a324a7 |
414 | * |
415 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
416 | * @ec *d@ = pointer to the destination |
417 | * @const ec *p@ = pointer to a source point |
418 | * |
419 | * Returns: The destination @d@. |
420 | * |
421 | * Use: An identity operation if your curve has no internal |
422 | * representation. (The field internal representation is still |
423 | * used.) |
424 | */ |
425 | |
426 | extern ec *ec_idin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
427 | extern ec *ec_idout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
428 | extern ec *ec_idfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
41a324a7 |
429 | |
8823192f |
430 | /* --- @ec_projin@, @ec_projout@, @ec_projfix@ --- * |
41a324a7 |
431 | * |
432 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
433 | * @ec *d@ = pointer to the destination |
434 | * @const ec *p@ = pointer to a source point |
435 | * |
436 | * Returns: The destination @d@. |
437 | * |
438 | * Use: Conversion functions if your curve operations use a |
439 | * projective representation. |
440 | */ |
441 | |
442 | extern ec *ec_projin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
443 | extern ec *ec_projout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
8823192f |
444 | extern ec *ec_projfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
b0ab12e6 |
445 | |
b085fd91 |
446 | /* --- @ec_stdsub@ --- * |
447 | * |
448 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
449 | * @ec *d@ = pointer to the destination |
41cb1beb |
450 | * @const ec *p, *q@ = the operand points |
b085fd91 |
451 | * |
452 | * Returns: The destination @d@. |
453 | * |
454 | * Use: Standard point subtraction operation, in terms of negation |
455 | * and addition. This isn't as efficient as a ready-made |
456 | * subtraction operator. |
457 | */ |
458 | |
41cb1beb |
459 | extern ec *ec_stdsub(ec_curve */*c*/, ec */*d*/, |
460 | const ec */*p*/, const ec */*q*/); |
b085fd91 |
461 | |
b0ab12e6 |
462 | /*----- Creating curves ---------------------------------------------------*/ |
463 | |
b085fd91 |
464 | /* --- @ec_destroycurve@ --- * |
465 | * |
466 | * Arguments: @ec_curve *c@ = pointer to an ellptic curve |
467 | * |
468 | * Returns: --- |
469 | * |
470 | * Use: Destroys a description of an elliptic curve. |
471 | */ |
472 | |
473 | extern void ec_destroycurve(ec_curve */*c*/); |
474 | |
475 | /* --- @ec_prime@, @ec_primeproj@ --- * |
b0ab12e6 |
476 | * |
dbfee00a |
477 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
b0ab12e6 |
478 | * @mp *a, *b@ = the coefficients for this curve |
479 | * |
480 | * Returns: A pointer to the curve. |
481 | * |
482 | * Use: Creates a curve structure for an elliptic curve defined over |
b085fd91 |
483 | * a prime field. The @primeproj@ variant uses projective |
484 | * coordinates, which can be a win. |
b0ab12e6 |
485 | */ |
486 | |
487 | extern ec_curve *ec_prime(field */*f*/, mp */*a*/, mp */*b*/); |
b085fd91 |
488 | extern ec_curve *ec_primeproj(field */*f*/, mp */*a*/, mp */*b*/); |
b0ab12e6 |
489 | |
ceb3f0c0 |
490 | /* --- @ec_bin@, @ec_binproj@ --- * |
b0ab12e6 |
491 | * |
492 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
493 | * @mp *a, *b@ = the coefficients for this curve |
494 | * |
495 | * Returns: A pointer to the curve. |
496 | * |
ceb3f0c0 |
497 | * Use: Creates a curve structure for an elliptic curve defined over |
498 | * a binary field. The @binproj@ variant uses projective |
499 | * coordinates, which can be a win. |
b0ab12e6 |
500 | */ |
501 | |
502 | extern ec_curve *ec_bin(field */*f*/, mp */*a*/, mp */*b*/); |
ceb3f0c0 |
503 | extern ec_curve *ec_binproj(field */*f*/, mp */*a*/, mp */*b*/); |
b0ab12e6 |
504 | |
432c4e18 |
505 | /*----- Curve parameter sets ----------------------------------------------*/ |
506 | |
507 | /* --- @ec_curveparse@ --- * |
508 | * |
509 | * Arguments: @qd_parse *qd@ = parser context |
510 | * |
511 | * Returns: Elliptic curve pointer if OK, or null. |
512 | * |
513 | * Use: Parses an elliptic curve description, which has the form |
514 | * |
515 | * * a field description |
516 | * * an optional `/' |
517 | * * `prime', `primeproj', `bin', or `binproj' |
518 | * * an optional `:' |
519 | * * the %$a$% parameter |
520 | * * an optional `,' |
521 | * * the %$b$% parameter |
522 | */ |
523 | |
524 | extern ec_curve *ec_curveparse(qd_parse */*qd*/); |
525 | |
526 | /* --- @ec_ptparse@ --- * |
527 | * |
528 | * Arguments: @qd_parse *qd@ = parser context |
529 | * @ec *p@ = where to put the point |
530 | * |
531 | * Returns: The point address, or null. |
532 | * |
533 | * Use: Parses an elliptic curve point. This has the form |
534 | * |
535 | * * %$x$%-coordinate |
536 | * * optional `,' |
537 | * * %$y$%-coordinate |
538 | */ |
539 | |
540 | extern ec *ec_ptparse(qd_parse */*qd*/, ec */*p*/); |
541 | |
542 | /* --- @ec_infoparse@ --- * |
543 | * |
544 | * Arguments: @qd_parse *qd@ = parser context |
545 | * @ec_info *ei@ = curve information block, currently |
546 | * uninitialized |
547 | * |
548 | * Returns: Zero on success, nonzero on failure. |
549 | * |
550 | * Use: Parses an elliptic curve information string, and stores the |
551 | * information in @ei@. This has the form |
552 | * |
553 | * * elliptic curve description |
554 | * * optional `/' |
555 | * * common point |
556 | * * optional `:' |
557 | * * group order |
558 | * * optional `*' |
559 | * * cofactor |
560 | */ |
561 | |
562 | extern int ec_infoparse(qd_parse */*qd*/, ec_info */*ei*/); |
563 | |
564 | /* --- @ec_getinfo@ --- * |
565 | * |
566 | * Arguments: @ec_info *ei@ = where to write the information |
567 | * @const char *p@ = string describing a curve |
568 | * |
569 | * Returns: Null on success, or a pointer to an error message. |
570 | * |
571 | * Use: Parses out information about a curve. The string is either a |
572 | * standard curve name, or a curve info string. |
573 | */ |
574 | |
575 | extern const char *ec_getinfo(ec_info */*ei*/, const char */*p*/); |
576 | |
577 | /* --- @ec_freeinfo@ --- * |
578 | * |
579 | * Arguments: @ec_info *ei@ = elliptic curve information block to free |
580 | * |
581 | * Returns: --- |
582 | * |
583 | * Use: Frees the information block. |
584 | */ |
585 | |
586 | extern void ec_freeinfo(ec_info */*ei*/); |
587 | |
588 | /* --- @ec_checkinfo@ --- * |
589 | * |
590 | * Arguments: @const ec_info *ei@ = elliptic curve information block |
591 | * |
592 | * Returns: Null if OK, or pointer to error message. |
593 | * |
594 | * Use: Checks an elliptic curve according to the rules in SEC1. |
595 | */ |
596 | |
597 | extern const char *ec_checkinfo(const ec_info */*ei*/, grand */*gr*/); |
598 | |
b0ab12e6 |
599 | /*----- That's all, folks -------------------------------------------------*/ |
600 | |
601 | #ifdef __cplusplus |
602 | } |
603 | #endif |
604 | |
605 | #endif |