/* -*-c-*-
*
- * $Id: field.h,v 1.4 2004/03/21 22:52:06 mdw Exp $
+ * $Id$
*
* Definitions for field arithmetic
*
* (c) 2000 Straylight/Edgeware
*/
-/*----- Licensing notice --------------------------------------------------*
+/*----- Licensing notice --------------------------------------------------*
*
* This file is part of Catacomb.
*
* 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: field.h,v $
- * Revision 1.4 2004/03/21 22:52:06 mdw
- * Merge and close elliptic curve branch.
- *
- * Revision 1.3.4.2 2004/03/21 22:39:46 mdw
- * Elliptic curves on binary fields work.
- *
- * Revision 1.3.4.1 2004/03/20 00:13:31 mdw
- * Projective coordinates for prime curves
- *
- * Revision 1.3 2002/01/13 13:48:44 mdw
- * Further progress.
- *
- * Revision 1.2 2001/05/07 17:30:13 mdw
- * Add an internal-representation no-op function.
- *
- * Revision 1.1 2001/04/29 18:12:33 mdw
- * Prototype version.
- *
- */
-
#ifndef CATACOMB_FIELD_H
#define CATACOMB_FIELD_H
/*----- Header files ------------------------------------------------------*/
+#ifndef CATACOMB_GRAND_H
+# include "grand.h"
+#endif
+
#ifndef CATACOMB_MP_H
# include "mp.h"
#endif
+#ifndef CATACOMB_QDPARSE_H
+# include "qdparse.h"
+#endif
+
/*----- Data structures ---------------------------------------------------*/
typedef struct field {
const struct field_ops *ops; /* Field operations */
mp *zero, *one; /* Identities in the field */
+ mp *m; /* Modulus (prime and binary) */
+ unsigned long nbits; /* Length of field element in bits */
+ size_t noctets; /* Length of element in octets */
+ mp *q; /* Number of elements in field */
} field;
+enum {
+ FTY_PRIME,
+ FTY_BINARY
+};
+
typedef struct field_ops {
+ /* --- General information --- */
+
+ unsigned ty; /* What kind of field this is */
+ const char *name; /* Human-readable name string */
+
/* --- Universal operations --- */
void (*destroy)(field */*f*/);
+ mp *(*rand)(field */*f*/, mp */*d*/, grand */*r*/);
+ int (*samep)(field */*f*/, field */*g*/);
mp *(*in)(field */*f*/, mp */*d*/, mp */*x*/);
mp *(*out)(field */*f*/, mp */*d*/, mp */*x*/);
} field_ops;
+#define F_TYPE(f) (f)->ops->ty
+#define F_NAME(f) (f)->ops->name
+
#define F_DESTROY(f) (f)->ops->destroy((f))
+#define F_RAND(f, d, r) (f)->ops->rand((f), (d), (r))
+#define F_SAMEP(f, g) (f)->ops->samep((f), (g))
#define F_IN(f, d, x) (f)->ops->in((f), (d), (x))
#define F_OUT(f, d, x) (f)->ops->out((f), (d), (x))
extern mp *field_id(field */*f*/, mp */*d*/, mp */*x*/);
+/* --- @field_samep@ --- *
+ *
+ * Arguments: @field *f, *g@ = two fields
+ *
+ * Returns: Nonzero if the fields are identical (not just isomorphic).
+ *
+ * Use: Checks for sameness of fields. This function does the full
+ * check, not just the field-type-specific check done by the
+ * @sampep@ field operation.
+ */
+
+extern int field_samep(field */*f*/, field */*g*/);
+
+/* --- @field_stdsamep@ --- *
+ *
+ * Arguments: @field *f, *g@ = two fields
+ *
+ * Returns: Nonzero if the fields are identical (not just isomorphic).
+ *
+ * Use: Standard sameness check, based on equality of the @m@
+ * member.
+ */
+
+extern int field_stdsamep(field */*f*/, field */*g*/);
+
+/*----- Arithmetic --------------------------------------------------------*/
+
+/* --- @field_exp@ --- *
+ *
+ * Arguments: @field *f@ = pointer to field
+ * @mp *d@ = fake destination
+ * @mp *a@ = base
+ * @mp *e@ = exponent
+ *
+ * Returns: Result, %$a^e$%.
+ *
+ * Use: Exponentiation in a finite field. Note that all quantities
+ * are in internal format. This is a generic implementation
+ * suitable for use with all fields and is not intended to be
+ * optimal.
+ */
+
+extern mp *field_exp(field */*f*/, mp */*d*/, mp */*a*/, mp */*e*/);
+
/*----- Creating fields ---------------------------------------------------*/
/* --- @field_prime@ --- *
extern field *field_prime(mp */*p*/);
+/* --- @field_niceprime@ --- *
+ *
+ * Arguments: @mp *p@ = the characteristic of the field
+ *
+ * Returns: A pointer to the field, or null.
+ *
+ * Use: Creates a field structure for a prime field of size %$p$%,
+ * using efficient reduction for nice primes.
+ */
+
+extern field *field_niceprime(mp */*p*/);
+
/* --- @field_binpoly@ --- *
*
* Arguments: @mp *p@ = an irreducible polynomial over %$\gf{2}$%
extern field *field_binpoly(mp */*p*/);
+/* --- @field_binnorm@ --- *
+ *
+ * Arguments: @mp *p@ = the reduction polynomial
+ * @mp *beta@ = representation of normal point
+ *
+ * Returns: A pointer to the field.
+ *
+ * Use: Creates a field structure for a binary field mod @p@ which
+ * uses a normal basis representation externally. Computations
+ * are still done on a polynomial-basis representation.
+ */
+
+extern field *field_binnorm(mp */*p*/, mp */*beta*/);
+
+/* --- @field_parse@ --- *
+ *
+ * Arguments: @qd_parse *qd@ = parser context
+ *
+ * Returns: Field pointer if OK, or null.
+ *
+ * Use: Parses a field description, which has the form
+ *
+ * * `prime', `niceprime', `binpoly', or `binnorm'
+ * * an optional `:'
+ * * the field modulus
+ * * for `binnorm', an optional `,' and the beta value
+ */
+
+extern field *field_parse(qd_parse */*qd*/);
+
/*----- That's all, folks -------------------------------------------------*/
#ifdef __cplusplus
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