X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/ec.h diff --git a/ec.h b/ec.h deleted file mode 100644 index ac0b8fc1..00000000 --- a/ec.h +++ /dev/null @@ -1,618 +0,0 @@ -/* -*-c-*- - * - * $Id$ - * - * Elliptic curve definitions - * - * (c) 2001 Straylight/Edgeware - */ - -/*----- Licensing notice --------------------------------------------------* - * - * This file is part of Catacomb. - * - * Catacomb is free software; you can redistribute it and/or modify - * it under the terms of the GNU Library General Public License as - * published by the Free Software Foundation; either version 2 of the - * License, or (at your option) any later version. - * - * Catacomb is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU Library General Public License for more details. - * - * You should have received a copy of the GNU Library General Public - * License along with Catacomb; if not, write to the Free - * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, - * MA 02111-1307, USA. - */ - -#ifndef CATACOMB_EC_H -#define CATACOMB_EC_H - -#ifdef __cplusplus - extern "C" { -#endif - -/*----- Header files ------------------------------------------------------*/ - -#ifndef CATACOMB_FIELD_H -# include "field.h" -#endif - -#ifndef CATACOMB_MP_H -# include "mp.h" -#endif - -#ifndef CATACOMB_QDPARSE_H -# include "qdparse.h" -#endif - -/*----- Data structures ---------------------------------------------------*/ - -/* --- An elliptic curve representation --- */ - -typedef struct ec_curve { - const struct ec_ops *ops; /* Curve operations */ - field *f; /* Underlying field structure */ - mp *a, *b; /* Standard params (internal form) */ -} ec_curve; - -/* --- An elliptic curve point --- */ - -typedef struct ec { - mp *x, *y; /* Point coordinates */ - mp *z; /* Common denominator (or null) */ -} ec; - -/* --- A factor for simultaneous multiplication --- */ - -typedef struct ec_mulfactor { - ec base; /* The point */ - mp *exp; /* The exponent */ -} ec_mulfactor; - -/* --- Elliptic curve operations --- * - * - * All operations (apart from @destroy@ and @in@) are guaranteed to be - * performed on internal representations of points. - * - * (Historical note. We used to guarantee that the second to @add@ and @mul@ - * was the output of @in@ or @fix@, but this canonification turned out to - * make the precomputation in @ec_exp@ too slow. Projective implementations - * must therefore cope with a pair of arbitrary points.) - */ - -typedef struct ec_ops { - const char *name; - void (*destroy)(ec_curve */*c*/); - int (*samep)(ec_curve */*c*/, ec_curve */*d*/); - ec *(*in)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - ec *(*out)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - ec *(*fix)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - ec *(*find)(ec_curve */*c*/, ec */*d*/, mp */*x*/); - ec *(*neg)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - ec *(*add)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); - ec *(*sub)(ec_curve */*c*/, ec */*d*/, const ec */*p*/, const ec */*q*/); - ec *(*dbl)(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - int (*check)(ec_curve */*c*/, const ec */*p*/); -} ec_ops; - -#define EC_NAME(c) (c)->ops->name - -#define EC_SAMEP(c, d) (c)->ops->samep((c), (d)) -#define EC_IN(c, d, p) (c)->ops->in((c), (d), (p)) -#define EC_OUT(c, d, p) (c)->ops->out((c), (d), (p)) -#define EC_FIX(c, d, p) (c)->ops->fix((c), (d), (p)) - -#define EC_FIND(c, d, x) (c)->ops->find((c), (d), (x)) -#define EC_NEG(c, d, x) (c)->ops->neg((c), (d), (x)) -#define EC_ADD(c, d, p, q) (c)->ops->add((c), (d), (p), (q)) -#define EC_SUB(c, d, p, q) (c)->ops->sub((c), (d), (p), (q)) -#define EC_DBL(c, d, p) (c)->ops->dbl((c), (d), (p)) -#define EC_CHECK(c, p) (c)->ops->check((c), (p)) - -/* --- Elliptic curve parameters --- */ - -typedef struct ec_info { - ec_curve *c; /* The actual curve */ - ec g; /* The common point */ - mp *r; /* Order of %$g$% */ - mp *h; /* Cofactor %$h = \#E/r$% */ -} ec_info; - -/*----- Simple memory management things -----------------------------------*/ - -/* --- @ec_create@ --- * - * - * Arguments: @ec *p@ = pointer to an elliptic-curve point - * - * Returns: The argument @p@. - * - * Use: Initializes a new point. The initial value is the additive - * identity (which is universal for all curves). - */ - -#define EC_INIT { MP_NEW, MP_NEW, MP_NEW } - -#define EC_CREATE(p) do { \ - ec *_p = (p); \ - _p->x = _p->y = _p->z = MP_NEW; \ -} while (0) - -extern ec *ec_create(ec */*p*/); - -/* --- @ec_destroy@ --- * - * - * Arguments: @ec *p@ = pointer to an elliptic-curve point - * - * Returns: --- - * - * Use: Destroys a point, making it invalid. - */ - -#define EC_DESTROY(p) do { \ - ec *_p = (p); \ - if (!EC_ATINF(_p)) { \ - MP_DROP(_p->x); \ - MP_DROP(_p->y); \ - if (_p->z) MP_DROP(_p->z); \ - } \ -} while (0) - -extern void ec_destroy(ec */*p*/); - -/* --- @ec_atinf@ --- * - * - * Arguments: @const ec *p@ = pointer to a point - * - * Returns: Nonzero if %$p = O$% is the point at infinity, zero - * otherwise. - */ - -#define EC_ATINF(p) ((p)->x == MP_NEW || (p)->x == MP_NEWSEC) - -extern int ec_atinf(const ec */*p*/); - -/* --- @ec_setinf@ --- * - * - * Arguments: @ec *p@ = pointer to a point - * - * Returns: The argument @p@. - * - * Use: Sets the given point to be the point %$O$% at infinity. - */ - -#define EC_SETINF(p) do { \ - ec *_p = (p); \ - if (!EC_ATINF(_p)) { \ - MP_DROP(_p->x); \ - MP_DROP(_p->y); \ - if (_p->z) MP_DROP(_p->z); \ - _p->x = _p->y = _p->z = MP_NEW; \ - _p->y = MP_NEW; \ - _p->z = MP_NEW; \ - } \ -} while (0) - -extern ec *ec_setinf(ec */*p*/); - -/* --- @ec_copy@ --- * - * - * Arguments: @ec *d@ = pointer to destination point - * @const ec *p@ = pointer to source point - * - * Returns: The destination @d@. - * - * Use: Creates a copy of an elliptic curve point. - */ - -#define EC_COPY(d, p) do { \ - ec *_d = (d); \ - const ec *_p = (p); \ - if (d != p) { \ - EC_DESTROY(d); \ - if (EC_ATINF(p)) \ - _d->x = _d->y = _d->z = MP_NEW; \ - else { \ - _d->x = MP_COPY(_p->x); \ - _d->y = MP_COPY(_p->y); \ - _d->z = _p->z ? MP_COPY(_p->z) : MP_NEW; \ - } \ - } \ -} while (0) - -extern ec *ec_copy(ec */*d*/, const ec */*p*/); - -/* --- @ec_eq@ --- * - * - * Arguments: @const ec *p, *q@ = two points - * - * Returns: Nonzero if the points are equal. Compares external-format - * points. - */ - -#define EC_EQ(p, q) \ - ((EC_ATINF(p) && EC_ATINF(q)) || \ - (!EC_ATINF(p) && !EC_ATINF(q) && \ - MP_EQ((p)->x, (q)->x) && \ - MP_EQ((p)->y, (q)->y))) - -extern int ec_eq(const ec *p, const ec *q); - -/*----- Interesting arithmetic --------------------------------------------*/ - -/* --- @ec_samep@ --- * - * - * Arguments: @ec_curve *c, *d@ = two elliptic curves - * - * Returns: Nonzero if the curves are identical (not just isomorphic). - * - * Use: Checks for sameness of curves. This function does the full - * check, not just the curve-type-specific check done by the - * @sampep@ field operation. - */ - -extern int ec_samep(ec_curve */*c*/, ec_curve */*d*/); - -/* --- @ec_find@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @mp *x@ = a possible x-coordinate - * - * Returns: The destination if OK, or null if no point was found. - * - * Use: Finds a point on an elliptic curve with a given - * x-coordinate. If there is no point with the given - * %$x$%-coordinate, a null pointer is returned and the - * destination is left invalid. - */ - -extern ec *ec_find(ec_curve */*c*/, ec */*d*/, mp */*x*/); - -/* --- @ec_rand@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @grand *r@ = random number source - * - * Returns: The destination @d@. - * - * Use: Finds a random point on the given curve. - */ - -extern ec *ec_rand(ec_curve */*c*/, ec */*d*/, grand */*r*/); - -/* --- @ec_neg@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec *p@ = pointer to the operand point - * - * Returns: The destination point. - * - * Use: Computes the negation of the given point. - */ - -extern ec *ec_neg(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - -/* --- @ec_add@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec *p, *q@ = pointers to the operand points - * - * Returns: The destination @d@. - * - * Use: Adds two points on an elliptic curve. - */ - -extern ec *ec_add(ec_curve */*c*/, ec */*d*/, - const ec */*p*/, const ec */*q*/); - -/* --- @ec_sub@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec *p, *q@ = pointers to the operand points - * - * Returns: The destination @d@. - * - * Use: Subtracts one point from another on an elliptic curve. - */ - -extern ec *ec_sub(ec_curve */*c*/, ec */*d*/, - const ec */*p*/, const ec */*q*/); - -/* --- @ec_dbl@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec *p@ = pointer to the operand point - * - * Returns: The destination @d@. - * - * Use: Doubles a point on an elliptic curve. - */ - -extern ec *ec_dbl(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - -/* --- @ec_check@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @const ec *p@ = pointer to the point - * - * Returns: Zero if OK, nonzero if this is an invalid point. - * - * Use: Checks that a point is actually on an elliptic curve. - */ - -extern int ec_check(ec_curve */*c*/, const ec */*p*/); - -/* --- @ec_mul@, @ec_imul@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec *p@ = pointer to the generator point - * @mp *n@ = integer multiplier - * - * Returns: The destination @d@. - * - * Use: Multiplies a point by a scalar, returning %$n p$%. The - * @imul@ variant uses internal representations for argument - * and result. - */ - -extern ec *ec_mul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); -extern ec *ec_imul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/); - -/* --- @ec_mmul@, @ec_immul@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination point - * @const ec_mulfactor *f@ = pointer to vector of factors - * @size_t n@ = number of factors - * - * Returns: The destination @d@. - * - * Use: Does simultaneous point multiplication. The @immul@ variant - * uses internal representations for arguments and result. - */ - -extern ec *ec_mmul(ec_curve */*c*/, ec */*d*/, - const ec_mulfactor */*f*/, size_t /*n*/); -extern ec *ec_immul(ec_curve */*c*/, ec */*d*/, - const ec_mulfactor */*f*/, size_t /*n*/); - -/*----- Standard curve operations -----------------------------------------*/ - -/* --- @ec_stdsamep@ --- * - * - * Arguments: @ec_curve *c, *d@ = two elliptic curves - * - * Returns: Nonzero if the curves are identical (not just isomorphic). - * - * Use: Simple sameness check on @a@ and @b@ curve members. - */ - -extern int ec_stdsamep(ec_curve */*c*/, ec_curve */*d*/); - -/* --- @ec_idin@, @ec_idout@, @ec_idfix@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination - * @const ec *p@ = pointer to a source point - * - * Returns: The destination @d@. - * - * Use: An identity operation if your curve has no internal - * representation. (The field internal representation is still - * used.) - */ - -extern ec *ec_idin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); -extern ec *ec_idout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); -extern ec *ec_idfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - -/* --- @ec_projin@, @ec_projout@, @ec_projfix@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination - * @const ec *p@ = pointer to a source point - * - * Returns: The destination @d@. - * - * Use: Conversion functions if your curve operations use a - * projective representation. - */ - -extern ec *ec_projin(ec_curve */*c*/, ec */*d*/, const ec */*p*/); -extern ec *ec_projout(ec_curve */*c*/, ec */*d*/, const ec */*p*/); -extern ec *ec_projfix(ec_curve */*c*/, ec */*d*/, const ec */*p*/); - -/* --- @ec_stdsub@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an elliptic curve - * @ec *d@ = pointer to the destination - * @const ec *p, *q@ = the operand points - * - * Returns: The destination @d@. - * - * Use: Standard point subtraction operation, in terms of negation - * and addition. This isn't as efficient as a ready-made - * subtraction operator. - */ - -extern ec *ec_stdsub(ec_curve */*c*/, ec */*d*/, - const ec */*p*/, const ec */*q*/); - -/*----- Creating curves ---------------------------------------------------*/ - -/* --- @ec_destroycurve@ --- * - * - * Arguments: @ec_curve *c@ = pointer to an ellptic curve - * - * Returns: --- - * - * Use: Destroys a description of an elliptic curve. - */ - -extern void ec_destroycurve(ec_curve */*c*/); - -/* --- @ec_prime@, @ec_primeproj@ --- * - * - * Arguments: @field *f@ = the underlying field for this elliptic curve - * @mp *a, *b@ = the coefficients for this curve - * - * Returns: A pointer to the curve, or null. - * - * Use: Creates a curve structure for an elliptic curve defined over - * a prime field. The @primeproj@ variant uses projective - * coordinates, which can be a win. - */ - -extern ec_curve *ec_prime(field */*f*/, mp */*a*/, mp */*b*/); -extern ec_curve *ec_primeproj(field */*f*/, mp */*a*/, mp */*b*/); - -/* --- @ec_bin@, @ec_binproj@ --- * - * - * Arguments: @field *f@ = the underlying field for this elliptic curve - * @mp *a, *b@ = the coefficients for this curve - * - * Returns: A pointer to the curve, or null. - * - * Use: Creates a curve structure for an elliptic curve defined over - * a binary field. The @binproj@ variant uses projective - * coordinates, which can be a win. - */ - -extern ec_curve *ec_bin(field */*f*/, mp */*a*/, mp */*b*/); -extern ec_curve *ec_binproj(field */*f*/, mp */*a*/, mp */*b*/); - -/*----- Curve parameter sets ----------------------------------------------*/ - -/* --- @ec_curveparse@ --- * - * - * Arguments: @qd_parse *qd@ = parser context - * - * Returns: Elliptic curve pointer if OK, or null. - * - * Use: Parses an elliptic curve description, which has the form - * - * * a field description - * * an optional `;' - * * `prime', `primeproj', `bin', or `binproj' - * * an optional `:' - * * the %$a$% parameter - * * an optional `,' - * * the %$b$% parameter - */ - -extern ec_curve *ec_curveparse(qd_parse */*qd*/); - -/* --- @ec_ptparse@ --- * - * - * Arguments: @qd_parse *qd@ = parser context - * @ec *p@ = where to put the point - * - * Returns: The point address, or null. - * - * Use: Parses an elliptic curve point. This has the form - * - * * %$x$%-coordinate - * * optional `,' - * * %$y$%-coordinate - */ - -extern ec *ec_ptparse(qd_parse */*qd*/, ec */*p*/); - -/* --- @ec_infoparse@ --- * - * - * Arguments: @qd_parse *qd@ = parser context - * @ec_info *ei@ = curve information block, currently - * uninitialized - * - * Returns: Zero on success, nonzero on failure. - * - * Use: Parses an elliptic curve information string, and stores the - * information in @ei@. This has the form - * - * * elliptic curve description - * * optional `;' - * * common point - * * optional `:' - * * group order - * * optional `*' - * * cofactor - */ - -extern int ec_infoparse(qd_parse */*qd*/, ec_info */*ei*/); - -/* --- @ec_infofromdata@ --- * - * - * Arguments: @ec_info *ei@ = where to write the information - * @ecdata *ed@ = raw data - * - * Returns: --- - * - * Use: Loads elliptic curve information about one of the standard - * curves. - */ - -struct ecdata; -extern void ec_infofromdata(ec_info */*ei*/, struct ecdata */*ed*/); - -/* --- @ec_getinfo@ --- * - * - * Arguments: @ec_info *ei@ = where to write the information - * @const char *p@ = string describing a curve - * - * Returns: Null on success, or a pointer to an error message. - * - * Use: Parses out information about a curve. The string is either a - * standard curve name, or a curve info string. - */ - -extern const char *ec_getinfo(ec_info */*ei*/, const char */*p*/); - -/* --- @ec_sameinfop@ --- * - * - * Arguments: @ec_info *ei, *ej@ = two elliptic curve parameter sets - * - * Returns: Nonzero if the curves are identical (not just isomorphic). - * - * Use: Checks for sameness of curve parameters. - */ - -extern int ec_sameinfop(ec_info */*ei*/, ec_info */*ej*/); - -/* --- @ec_freeinfo@ --- * - * - * Arguments: @ec_info *ei@ = elliptic curve information block to free - * - * Returns: --- - * - * Use: Frees the information block. - */ - -extern void ec_freeinfo(ec_info */*ei*/); - -/* --- @ec_checkinfo@ --- * - * - * Arguments: @const ec_info *ei@ = elliptic curve information block - * - * Returns: Null if OK, or pointer to error message. - * - * Use: Checks an elliptic curve according to the rules in SEC1. - */ - -extern const char *ec_checkinfo(const ec_info */*ei*/, grand */*gr*/); - -/*----- That's all, folks -------------------------------------------------*/ - -#ifdef __cplusplus - } -#endif - -#endif