| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id$ |
| 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 | #ifndef CATACOMB_EC_H |
| 31 | #define CATACOMB_EC_H |
| 32 | |
| 33 | #ifdef __cplusplus |
| 34 | extern "C" { |
| 35 | #endif |
| 36 | |
| 37 | /*----- Header files ------------------------------------------------------*/ |
| 38 | |
| 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 |
| 50 | |
| 51 | /*----- Data structures ---------------------------------------------------*/ |
| 52 | |
| 53 | /* --- An elliptic curve representation --- */ |
| 54 | |
| 55 | typedef struct ec_curve { |
| 56 | const struct ec_ops *ops; /* Curve operations */ |
| 57 | field *f; /* Underlying field structure */ |
| 58 | mp *a, *b; /* Standard params (internal form) */ |
| 59 | } ec_curve; |
| 60 | |
| 61 | /* --- An elliptic curve point --- */ |
| 62 | |
| 63 | typedef struct ec { |
| 64 | mp *x, *y; /* Point coordinates */ |
| 65 | mp *z; /* Common denominator (or null) */ |
| 66 | } ec; |
| 67 | |
| 68 | /* --- A factor for simultaneous multiplication --- */ |
| 69 | |
| 70 | typedef struct ec_mulfactor { |
| 71 | ec base; /* The point */ |
| 72 | mp *exp; /* The exponent */ |
| 73 | } ec_mulfactor; |
| 74 | |
| 75 | /* --- Elliptic curve operations --- * |
| 76 | * |
| 77 | * All operations (apart from @destroy@ and @in@) are guaranteed to be |
| 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.) |
| 84 | */ |
| 85 | |
| 86 | typedef struct ec_ops { |
| 87 | const char *name; |
| 88 | void (*destroy)(ec_curve */*c*/); |
| 89 | int (*samep)(ec_curve */*c*/, ec_curve */*d*/); |
| 90 | ec *(*in)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 91 | ec *(*out)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 92 | ec *(*fix)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 93 | ec *(*find)(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
| 94 | ec *(*neg)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 95 | ec *(*add)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
| 96 | ec *(*sub)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); |
| 97 | ec *(*dbl)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 98 | int (*check)(ec_curve */*c*/, const ec */*p*/); |
| 99 | } ec_ops; |
| 100 | |
| 101 | #define EC_NAME(c) (c)->ops->name |
| 102 | |
| 103 | #define EC_SAMEP(c, d) (c)->ops->samep((c), (d)) |
| 104 | #define EC_IN(c, d, p) (c)->ops->in((c), (d), (p)) |
| 105 | #define EC_OUT(c, d, p) (c)->ops->out((c), (d), (p)) |
| 106 | #define EC_FIX(c, d, p) (c)->ops->fix((c), (d), (p)) |
| 107 | |
| 108 | #define EC_FIND(c, d, x) (c)->ops->find((c), (d), (x)) |
| 109 | #define EC_NEG(c, d, x) (c)->ops->neg((c), (d), (x)) |
| 110 | #define EC_ADD(c, d, p, q) (c)->ops->add((c), (d), (p), (q)) |
| 111 | #define EC_SUB(c, d, p, q) (c)->ops->sub((c), (d), (p), (q)) |
| 112 | #define EC_DBL(c, d, p) (c)->ops->dbl((c), (d), (p)) |
| 113 | #define EC_CHECK(c, p) (c)->ops->check((c), (p)) |
| 114 | |
| 115 | /* --- Elliptic curve parameters --- */ |
| 116 | |
| 117 | typedef struct ec_info { |
| 118 | ec_curve *c; /* The actual curve */ |
| 119 | ec g; /* The common point */ |
| 120 | mp *r; /* Order of %$g$% */ |
| 121 | mp *h; /* Cofactor %$h = \#E/r$% */ |
| 122 | } ec_info; |
| 123 | |
| 124 | /*----- Simple memory management things -----------------------------------*/ |
| 125 | |
| 126 | /* --- @ec_create@ --- * |
| 127 | * |
| 128 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
| 129 | * |
| 130 | * Returns: The argument @p@. |
| 131 | * |
| 132 | * Use: Initializes a new point. The initial value is the additive |
| 133 | * identity (which is universal for all curves). |
| 134 | */ |
| 135 | |
| 136 | #define EC_INIT { MP_NEW, MP_NEW, MP_NEW } |
| 137 | |
| 138 | #define EC_CREATE(p) do { \ |
| 139 | ec *_p = (p); \ |
| 140 | _p->x = _p->y = _p->z = MP_NEW; \ |
| 141 | } while (0) |
| 142 | |
| 143 | extern ec *ec_create(ec */*p*/); |
| 144 | |
| 145 | /* --- @ec_destroy@ --- * |
| 146 | * |
| 147 | * Arguments: @ec *p@ = pointer to an elliptic-curve point |
| 148 | * |
| 149 | * Returns: --- |
| 150 | * |
| 151 | * Use: Destroys a point, making it invalid. |
| 152 | */ |
| 153 | |
| 154 | #define EC_DESTROY(p) do { \ |
| 155 | ec *_p = (p); \ |
| 156 | if (!EC_ATINF(_p)) { \ |
| 157 | MP_DROP(_p->x); \ |
| 158 | MP_DROP(_p->y); \ |
| 159 | if (_p->z) MP_DROP(_p->z); \ |
| 160 | } \ |
| 161 | } while (0) |
| 162 | |
| 163 | extern void ec_destroy(ec */*p*/); |
| 164 | |
| 165 | /* --- @ec_atinf@ --- * |
| 166 | * |
| 167 | * Arguments: @const ec *p@ = pointer to a point |
| 168 | * |
| 169 | * Returns: Nonzero if %$p = O$% is the point at infinity, zero |
| 170 | * otherwise. |
| 171 | */ |
| 172 | |
| 173 | #define EC_ATINF(p) ((p)->x == MP_NEW || (p)->x == MP_NEWSEC) |
| 174 | |
| 175 | extern int ec_atinf(const ec */*p*/); |
| 176 | |
| 177 | /* --- @ec_setinf@ --- * |
| 178 | * |
| 179 | * Arguments: @ec *p@ = pointer to a point |
| 180 | * |
| 181 | * Returns: The argument @p@. |
| 182 | * |
| 183 | * Use: Sets the given point to be the point %$O$% at infinity. |
| 184 | */ |
| 185 | |
| 186 | #define EC_SETINF(p) do { \ |
| 187 | ec *_p = (p); \ |
| 188 | if (!EC_ATINF(_p)) { \ |
| 189 | MP_DROP(_p->x); \ |
| 190 | MP_DROP(_p->y); \ |
| 191 | if (_p->z) MP_DROP(_p->z); \ |
| 192 | _p->x = _p->y = _p->z = MP_NEW; \ |
| 193 | _p->y = MP_NEW; \ |
| 194 | _p->z = MP_NEW; \ |
| 195 | } \ |
| 196 | } while (0) |
| 197 | |
| 198 | extern ec *ec_setinf(ec */*p*/); |
| 199 | |
| 200 | /* --- @ec_copy@ --- * |
| 201 | * |
| 202 | * Arguments: @ec *d@ = pointer to destination point |
| 203 | * @const ec *p@ = pointer to source point |
| 204 | * |
| 205 | * Returns: The destination @d@. |
| 206 | * |
| 207 | * Use: Creates a copy of an elliptic curve point. |
| 208 | */ |
| 209 | |
| 210 | #define EC_COPY(d, p) do { \ |
| 211 | ec *_d = (d); \ |
| 212 | const ec *_p = (p); \ |
| 213 | if (d != p) { \ |
| 214 | EC_DESTROY(d); \ |
| 215 | if (EC_ATINF(p)) \ |
| 216 | _d->x = _d->y = _d->z = MP_NEW; \ |
| 217 | else { \ |
| 218 | _d->x = MP_COPY(_p->x); \ |
| 219 | _d->y = MP_COPY(_p->y); \ |
| 220 | _d->z = _p->z ? MP_COPY(_p->z) : MP_NEW; \ |
| 221 | } \ |
| 222 | } \ |
| 223 | } while (0) |
| 224 | |
| 225 | extern ec *ec_copy(ec */*d*/, const ec */*p*/); |
| 226 | |
| 227 | /* --- @ec_eq@ --- * |
| 228 | * |
| 229 | * Arguments: @const ec *p, *q@ = two points |
| 230 | * |
| 231 | * Returns: Nonzero if the points are equal. Compares external-format |
| 232 | * points. |
| 233 | */ |
| 234 | |
| 235 | #define EC_EQ(p, q) \ |
| 236 | ((EC_ATINF(p) && EC_ATINF(q)) || \ |
| 237 | (!EC_ATINF(p) && !EC_ATINF(q) && \ |
| 238 | MP_EQ((p)->x, (q)->x) && \ |
| 239 | MP_EQ((p)->y, (q)->y))) |
| 240 | |
| 241 | extern int ec_eq(const ec *p, const ec *q); |
| 242 | |
| 243 | /*----- Interesting arithmetic --------------------------------------------*/ |
| 244 | |
| 245 | /* --- @ec_samep@ --- * |
| 246 | * |
| 247 | * Arguments: @ec_curve *c, *d@ = two elliptic curves |
| 248 | * |
| 249 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
| 250 | * |
| 251 | * Use: Checks for sameness of curves. This function does the full |
| 252 | * check, not just the curve-type-specific check done by the |
| 253 | * @sampep@ field operation. |
| 254 | */ |
| 255 | |
| 256 | extern int ec_samep(ec_curve */*c*/, ec_curve */*d*/); |
| 257 | |
| 258 | /* --- @ec_find@ --- * |
| 259 | * |
| 260 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 261 | * @ec *d@ = pointer to the destination point |
| 262 | * @mp *x@ = a possible x-coordinate |
| 263 | * |
| 264 | * Returns: The destination if OK, or null if no point was found. |
| 265 | * |
| 266 | * Use: Finds a point on an elliptic curve with a given |
| 267 | * x-coordinate. If there is no point with the given |
| 268 | * %$x$%-coordinate, a null pointer is returned and the |
| 269 | * destination is left invalid. |
| 270 | */ |
| 271 | |
| 272 | extern ec *ec_find(ec_curve */*c*/, ec */*d*/, mp */*x*/); |
| 273 | |
| 274 | /* --- @ec_rand@ --- * |
| 275 | * |
| 276 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 277 | * @ec *d@ = pointer to the destination point |
| 278 | * @grand *r@ = random number source |
| 279 | * |
| 280 | * Returns: The destination @d@. |
| 281 | * |
| 282 | * Use: Finds a random point on the given curve. |
| 283 | */ |
| 284 | |
| 285 | extern ec *ec_rand(ec_curve */*c*/, ec */*d*/, grand */*r*/); |
| 286 | |
| 287 | /* --- @ec_neg@ --- * |
| 288 | * |
| 289 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 290 | * @ec *d@ = pointer to the destination point |
| 291 | * @const ec *p@ = pointer to the operand point |
| 292 | * |
| 293 | * Returns: The destination point. |
| 294 | * |
| 295 | * Use: Computes the negation of the given point. |
| 296 | */ |
| 297 | |
| 298 | extern ec *ec_neg(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 299 | |
| 300 | /* --- @ec_add@ --- * |
| 301 | * |
| 302 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 303 | * @ec *d@ = pointer to the destination point |
| 304 | * @const ec *p, *q@ = pointers to the operand points |
| 305 | * |
| 306 | * Returns: The destination @d@. |
| 307 | * |
| 308 | * Use: Adds two points on an elliptic curve. |
| 309 | */ |
| 310 | |
| 311 | extern ec *ec_add(ec_curve */*c*/, ec */*d*/, |
| 312 | const ec */*p*/, const ec */*q*/); |
| 313 | |
| 314 | /* --- @ec_sub@ --- * |
| 315 | * |
| 316 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 317 | * @ec *d@ = pointer to the destination point |
| 318 | * @const ec *p, *q@ = pointers to the operand points |
| 319 | * |
| 320 | * Returns: The destination @d@. |
| 321 | * |
| 322 | * Use: Subtracts one point from another on an elliptic curve. |
| 323 | */ |
| 324 | |
| 325 | extern ec *ec_sub(ec_curve */*c*/, ec */*d*/, |
| 326 | const ec */*p*/, const ec */*q*/); |
| 327 | |
| 328 | /* --- @ec_dbl@ --- * |
| 329 | * |
| 330 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 331 | * @ec *d@ = pointer to the destination point |
| 332 | * @const ec *p@ = pointer to the operand point |
| 333 | * |
| 334 | * Returns: The destination @d@. |
| 335 | * |
| 336 | * Use: Doubles a point on an elliptic curve. |
| 337 | */ |
| 338 | |
| 339 | extern ec *ec_dbl(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 340 | |
| 341 | /* --- @ec_check@ --- * |
| 342 | * |
| 343 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 344 | * @const ec *p@ = pointer to the point |
| 345 | * |
| 346 | * Returns: Zero if OK, nonzero if this is an invalid point. |
| 347 | * |
| 348 | * Use: Checks that a point is actually on an elliptic curve. |
| 349 | */ |
| 350 | |
| 351 | extern int ec_check(ec_curve */*c*/, const ec */*p*/); |
| 352 | |
| 353 | /* --- @ec_mul@, @ec_imul@ --- * |
| 354 | * |
| 355 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 356 | * @ec *d@ = pointer to the destination point |
| 357 | * @const ec *p@ = pointer to the generator point |
| 358 | * @mp *n@ = integer multiplier |
| 359 | * |
| 360 | * Returns: The destination @d@. |
| 361 | * |
| 362 | * Use: Multiplies a point by a scalar, returning %$n p$%. The |
| 363 | * @imul@ variant uses internal representations for argument |
| 364 | * and result. |
| 365 | */ |
| 366 | |
| 367 | extern ec *ec_mul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
| 368 | extern ec *ec_imul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); |
| 369 | |
| 370 | /* --- @ec_mmul@, @ec_immul@ --- * |
| 371 | * |
| 372 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 373 | * @ec *d@ = pointer to the destination point |
| 374 | * @const ec_mulfactor *f@ = pointer to vector of factors |
| 375 | * @size_t n@ = number of factors |
| 376 | * |
| 377 | * Returns: The destination @d@. |
| 378 | * |
| 379 | * Use: Does simultaneous point multiplication. The @immul@ variant |
| 380 | * uses internal representations for arguments and result. |
| 381 | */ |
| 382 | |
| 383 | extern ec *ec_mmul(ec_curve */*c*/, ec */*d*/, |
| 384 | const ec_mulfactor */*f*/, size_t /*n*/); |
| 385 | extern ec *ec_immul(ec_curve */*c*/, ec */*d*/, |
| 386 | const ec_mulfactor */*f*/, size_t /*n*/); |
| 387 | |
| 388 | /*----- Standard curve operations -----------------------------------------*/ |
| 389 | |
| 390 | /* --- @ec_stdsamep@ --- * |
| 391 | * |
| 392 | * Arguments: @ec_curve *c, *d@ = two elliptic curves |
| 393 | * |
| 394 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
| 395 | * |
| 396 | * Use: Simple sameness check on @a@ and @b@ curve members. |
| 397 | */ |
| 398 | |
| 399 | extern int ec_stdsamep(ec_curve */*c*/, ec_curve */*d*/); |
| 400 | |
| 401 | /* --- @ec_idin@, @ec_idout@, @ec_idfix@ --- * |
| 402 | * |
| 403 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 404 | * @ec *d@ = pointer to the destination |
| 405 | * @const ec *p@ = pointer to a source point |
| 406 | * |
| 407 | * Returns: The destination @d@. |
| 408 | * |
| 409 | * Use: An identity operation if your curve has no internal |
| 410 | * representation. (The field internal representation is still |
| 411 | * used.) |
| 412 | */ |
| 413 | |
| 414 | extern ec *ec_idin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 415 | extern ec *ec_idout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 416 | extern ec *ec_idfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 417 | |
| 418 | /* --- @ec_projin@, @ec_projout@, @ec_projfix@ --- * |
| 419 | * |
| 420 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 421 | * @ec *d@ = pointer to the destination |
| 422 | * @const ec *p@ = pointer to a source point |
| 423 | * |
| 424 | * Returns: The destination @d@. |
| 425 | * |
| 426 | * Use: Conversion functions if your curve operations use a |
| 427 | * projective representation. |
| 428 | */ |
| 429 | |
| 430 | extern ec *ec_projin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 431 | extern ec *ec_projout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 432 | extern ec *ec_projfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); |
| 433 | |
| 434 | /* --- @ec_stdsub@ --- * |
| 435 | * |
| 436 | * Arguments: @ec_curve *c@ = pointer to an elliptic curve |
| 437 | * @ec *d@ = pointer to the destination |
| 438 | * @const ec *p, *q@ = the operand points |
| 439 | * |
| 440 | * Returns: The destination @d@. |
| 441 | * |
| 442 | * Use: Standard point subtraction operation, in terms of negation |
| 443 | * and addition. This isn't as efficient as a ready-made |
| 444 | * subtraction operator. |
| 445 | */ |
| 446 | |
| 447 | extern ec *ec_stdsub(ec_curve */*c*/, ec */*d*/, |
| 448 | const ec */*p*/, const ec */*q*/); |
| 449 | |
| 450 | /*----- Creating curves ---------------------------------------------------*/ |
| 451 | |
| 452 | /* --- @ec_destroycurve@ --- * |
| 453 | * |
| 454 | * Arguments: @ec_curve *c@ = pointer to an ellptic curve |
| 455 | * |
| 456 | * Returns: --- |
| 457 | * |
| 458 | * Use: Destroys a description of an elliptic curve. |
| 459 | */ |
| 460 | |
| 461 | extern void ec_destroycurve(ec_curve */*c*/); |
| 462 | |
| 463 | /* --- @ec_prime@, @ec_primeproj@ --- * |
| 464 | * |
| 465 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
| 466 | * @mp *a, *b@ = the coefficients for this curve |
| 467 | * |
| 468 | * Returns: A pointer to the curve, or null. |
| 469 | * |
| 470 | * Use: Creates a curve structure for an elliptic curve defined over |
| 471 | * a prime field. The @primeproj@ variant uses projective |
| 472 | * coordinates, which can be a win. |
| 473 | */ |
| 474 | |
| 475 | extern ec_curve *ec_prime(field */*f*/, mp */*a*/, mp */*b*/); |
| 476 | extern ec_curve *ec_primeproj(field */*f*/, mp */*a*/, mp */*b*/); |
| 477 | |
| 478 | /* --- @ec_bin@, @ec_binproj@ --- * |
| 479 | * |
| 480 | * Arguments: @field *f@ = the underlying field for this elliptic curve |
| 481 | * @mp *a, *b@ = the coefficients for this curve |
| 482 | * |
| 483 | * Returns: A pointer to the curve, or null. |
| 484 | * |
| 485 | * Use: Creates a curve structure for an elliptic curve defined over |
| 486 | * a binary field. The @binproj@ variant uses projective |
| 487 | * coordinates, which can be a win. |
| 488 | */ |
| 489 | |
| 490 | extern ec_curve *ec_bin(field */*f*/, mp */*a*/, mp */*b*/); |
| 491 | extern ec_curve *ec_binproj(field */*f*/, mp */*a*/, mp */*b*/); |
| 492 | |
| 493 | /*----- Curve parameter sets ----------------------------------------------*/ |
| 494 | |
| 495 | /* --- @ec_curveparse@ --- * |
| 496 | * |
| 497 | * Arguments: @qd_parse *qd@ = parser context |
| 498 | * |
| 499 | * Returns: Elliptic curve pointer if OK, or null. |
| 500 | * |
| 501 | * Use: Parses an elliptic curve description, which has the form |
| 502 | * |
| 503 | * * a field description |
| 504 | * * an optional `;' |
| 505 | * * `prime', `primeproj', `bin', or `binproj' |
| 506 | * * an optional `:' |
| 507 | * * the %$a$% parameter |
| 508 | * * an optional `,' |
| 509 | * * the %$b$% parameter |
| 510 | */ |
| 511 | |
| 512 | extern ec_curve *ec_curveparse(qd_parse */*qd*/); |
| 513 | |
| 514 | /* --- @ec_ptparse@ --- * |
| 515 | * |
| 516 | * Arguments: @qd_parse *qd@ = parser context |
| 517 | * @ec *p@ = where to put the point |
| 518 | * |
| 519 | * Returns: The point address, or null. |
| 520 | * |
| 521 | * Use: Parses an elliptic curve point. This has the form |
| 522 | * |
| 523 | * * %$x$%-coordinate |
| 524 | * * optional `,' |
| 525 | * * %$y$%-coordinate |
| 526 | */ |
| 527 | |
| 528 | extern ec *ec_ptparse(qd_parse */*qd*/, ec */*p*/); |
| 529 | |
| 530 | /* --- @ec_infoparse@ --- * |
| 531 | * |
| 532 | * Arguments: @qd_parse *qd@ = parser context |
| 533 | * @ec_info *ei@ = curve information block, currently |
| 534 | * uninitialized |
| 535 | * |
| 536 | * Returns: Zero on success, nonzero on failure. |
| 537 | * |
| 538 | * Use: Parses an elliptic curve information string, and stores the |
| 539 | * information in @ei@. This has the form |
| 540 | * |
| 541 | * * elliptic curve description |
| 542 | * * optional `;' |
| 543 | * * common point |
| 544 | * * optional `:' |
| 545 | * * group order |
| 546 | * * optional `*' |
| 547 | * * cofactor |
| 548 | */ |
| 549 | |
| 550 | extern int ec_infoparse(qd_parse */*qd*/, ec_info */*ei*/); |
| 551 | |
| 552 | /* --- @ec_infofromdata@ --- * |
| 553 | * |
| 554 | * Arguments: @ec_info *ei@ = where to write the information |
| 555 | * @ecdata *ed@ = raw data |
| 556 | * |
| 557 | * Returns: --- |
| 558 | * |
| 559 | * Use: Loads elliptic curve information about one of the standard |
| 560 | * curves. |
| 561 | */ |
| 562 | |
| 563 | struct ecdata; |
| 564 | extern void ec_infofromdata(ec_info */*ei*/, struct ecdata */*ed*/); |
| 565 | |
| 566 | /* --- @ec_getinfo@ --- * |
| 567 | * |
| 568 | * Arguments: @ec_info *ei@ = where to write the information |
| 569 | * @const char *p@ = string describing a curve |
| 570 | * |
| 571 | * Returns: Null on success, or a pointer to an error message. |
| 572 | * |
| 573 | * Use: Parses out information about a curve. The string is either a |
| 574 | * standard curve name, or a curve info string. |
| 575 | */ |
| 576 | |
| 577 | extern const char *ec_getinfo(ec_info */*ei*/, const char */*p*/); |
| 578 | |
| 579 | /* --- @ec_sameinfop@ --- * |
| 580 | * |
| 581 | * Arguments: @ec_info *ei, *ej@ = two elliptic curve parameter sets |
| 582 | * |
| 583 | * Returns: Nonzero if the curves are identical (not just isomorphic). |
| 584 | * |
| 585 | * Use: Checks for sameness of curve parameters. |
| 586 | */ |
| 587 | |
| 588 | extern int ec_sameinfop(ec_info */*ei*/, ec_info */*ej*/); |
| 589 | |
| 590 | /* --- @ec_freeinfo@ --- * |
| 591 | * |
| 592 | * Arguments: @ec_info *ei@ = elliptic curve information block to free |
| 593 | * |
| 594 | * Returns: --- |
| 595 | * |
| 596 | * Use: Frees the information block. |
| 597 | */ |
| 598 | |
| 599 | extern void ec_freeinfo(ec_info */*ei*/); |
| 600 | |
| 601 | /* --- @ec_checkinfo@ --- * |
| 602 | * |
| 603 | * Arguments: @const ec_info *ei@ = elliptic curve information block |
| 604 | * |
| 605 | * Returns: Null if OK, or pointer to error message. |
| 606 | * |
| 607 | * Use: Checks an elliptic curve according to the rules in SEC1. |
| 608 | */ |
| 609 | |
| 610 | extern const char *ec_checkinfo(const ec_info */*ei*/, grand */*gr*/); |
| 611 | |
| 612 | /*----- That's all, folks -------------------------------------------------*/ |
| 613 | |
| 614 | #ifdef __cplusplus |
| 615 | } |
| 616 | #endif |
| 617 | |
| 618 | #endif |