--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: ec.h,v 1.1 2001/04/29 18:12:33 mdw Exp $
+ *
+ * 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.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: ec.h,v $
+ * Revision 1.1 2001/04/29 18:12:33 mdw
+ * Prototype version.
+ *
+ */
+
+#ifndef CATACOMB_EC_H
+#define CATACOMB_EC_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "field.h"
+#include "mp.h"
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct ec_curve {
+ const struct ec_ops *ops; /* Curve operations */
+ field *f; /* Underlying field structure */
+} ec_curve;
+
+typedef struct ec {
+ mp *x, *y; /* Point coordinates */
+ mp *z; /* Common denominator (or null) */
+} ec;
+
+typedef struct ec_ops {
+ void (*destroy)(ec_curve */*c*/);
+ int (*find)(ec_curve */*c*/, ec */*d*/, mp */*x*/);
+ void (*add)(ec_curve */*c*/, ec */*d*/, ec */*p*/, ec */*q*/);
+ void (*dbl)(ec_curve */*c*/, ec */*d*/, ec */*p*/);
+} ec_ops;
+
+#define EC_DESTROY(c) (c)->ops->destroy((c))
+
+#define EC_FIND(c, d, x) (c)->ops->find((c), (d), (x))
+#define EC_ADD(c, d, p, q) (c)->ops->add((c), (d), (p), (q))
+#define EC_DBL(c, d, p) (c)->ops->dbl((c), (d), (p))
+
+/*----- Simple memory management things -----------------------------------*/
+
+/* --- @ec_create@ --- *
+ *
+ * Arguments: @ec *p@ = pointer to an elliptic-curve point
+ *
+ * Returns: ---
+ *
+ * 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 void 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: ---
+ *
+ * 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 void ec_setinf(ec */*p*/);
+
+/* --- @ec_copy@ --- *
+ *
+ * Arguments: @ec *d@ = pointer to destination point
+ * @const ec *p@ = pointer to source point
+ *
+ * Returns: ---
+ *
+ * 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 = _p->x; \
+ _d->y = _p->y; \
+ _d->z = _p->z; \
+ } \
+ } \
+} while (0)
+
+extern void ec_copy(ec */*d*/, const ec */*p*/);
+
+/*----- Interesting arithmetic --------------------------------------------*/
+
+/* --- @ec_denorm@ --- *
+ *
+ * Arguments: @ec_curve *c@ = pointer to an elliptic curve
+ * @ec *d@ = pointer to the destination point
+ * @const ec *p@ = pointer to the source point
+ *
+ * Returns: ---
+ *
+ * Use: Denormalizes the given point, converting to internal
+ * representations and setting the denominator to 1.
+ */
+
+extern void ec_denorm(ec_curve */*c*/, ec */*d*/, const ec */*p*/);
+
+/* --- @ec_norm@ --- *
+ *
+ * Arguments: @ec_curve *c@ = pointer to an elliptic curve
+ * @ec *d@ = pointer to the destination point
+ * @const ec *p@ = pointer to the source point
+ *
+ * Returns: ---
+ *
+ * Use: Normalizes the given point, by dividing through by the
+ * denominator and returning to external representation.
+ */
+
+extern void ec_norm(ec_curve */*c*/, ec */*d*/, const ec */*p*/);
+
+/* --- @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: Zero if OK, nonzero if there isn't a point there.
+ *
+ * Use: Finds a point on an elliptic curve with a given x-coordinate.
+ */
+
+extern void ec_find(ec_curve */*c*/, ec */*d*/, mp */*x*/);
+
+/* --- @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: ---
+ *
+ * Use: Adds two points on an elliptic curve.
+ */
+
+extern void ec_add(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: ---
+ *
+ * Use: Doubles a point on an elliptic curve.
+ */
+
+extern void ec_dbl(ec_curve */*c*/, ec */*d*/, const ec */*p*/);
+
+/* --- @ec_mul@ --- *
+ *
+ * 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: ---
+ *
+ * Use: Multiplies a point by a scalar, returning %$n p$%.
+ */
+
+extern void ec_mul(ec_curve */*c*/, ec */*d*/, const ec */*p*/, mp */*n*/);
+
+/*----- Creating curves ---------------------------------------------------*/
+
+/* --- @ec_prime@ --- *
+ *
+ * Arguments: @field *f@ = the underyling field for this elliptic curve
+ * @mp *a, *b@ = the coefficients for this curve
+ *
+ * Returns: A pointer to the curve.
+ *
+ * Use: Creates a curve structure for an elliptic curve defined over
+ * a prime field.
+ */
+
+extern ec_curve *ec_prime(field */*f*/, mp */*a*/, mp */*b*/);
+
+/* --- @ec_bin@ --- *
+ *
+ * Arguments: @field *f@ = the underlying field for this elliptic curve
+ * @mp *a, *b@ = the coefficients for this curve
+ *
+ * Returns: A pointer to the curve.
+ *
+ * Use: Creates a curve structure for a non-supersingular elliptic
+ * curve defined over a binary field.
+ */
+
+extern ec_curve *ec_bin(field */*f*/, mp */*a*/, mp */*b*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
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