--- /dev/null
+/* -*-c-*-
+ *
+ * Definitions for field arithmetic
+ *
+ * (c) 2000 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_FIELD_H
+#define CATACOMB_FIELD_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- 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*/);
+
+ int (*zerop)(field */*f*/, mp */*x*/);
+ mp *(*neg)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*add)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+ mp *(*sub)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+ mp *(*mul)(field */*f*/, mp */*d*/, mp */*x*/, mp */*y*/);
+ mp *(*sqr)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*inv)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*reduce)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*sqrt)(field */*f*/, mp */*d*/, mp */*x*/);
+
+ /* --- Operations for binary fields only --- */
+
+ mp *(*quadsolve)(field */*f*/, mp */*d*/, mp */*x*/);
+
+ /* --- Operations for prime fields only --- */
+
+ mp *(*dbl)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*tpl)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*qdl)(field */*f*/, mp */*d*/, mp */*x*/);
+ mp *(*hlv)(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))
+
+#define F_ZEROP(f, x) (f)->ops->zerop((f), (x))
+#define F_NEG(f, d, x) (f)->ops->neg((f), (d), (x))
+#define F_ADD(f, d, x, y) (f)->ops->add((f), (d), (x), (y))
+#define F_SUB(f, d, x, y) (f)->ops->sub((f), (d), (x), (y))
+#define F_MUL(f, d, x, y) (f)->ops->mul((f), (d), (x), (y))
+#define F_SQR(f, d, x) (f)->ops->sqr((f), (d), (x))
+#define F_INV(f, d, x) (f)->ops->inv((f), (d), (x))
+#define F_REDUCE(f, d, x) (f)->ops->reduce((f), (d), (x))
+#define F_SQRT(f, d, x) (f)->ops->sqrt((f), (d), (x))
+
+#define F_QUADSOLVE(f, d, x) (f)->ops->quadsolve((f), (d), (x))
+
+#define F_DBL(f, d, x) (f)->ops->dbl((f), (d), (x))
+#define F_TPL(f, d, x) (f)->ops->tpl((f), (d), (x))
+#define F_QDL(f, d, x) (f)->ops->qdl((f), (d), (x))
+#define F_HLV(f, d, x) (f)->ops->hlv((f), (d), (x))
+
+/*----- Helpful field operations ------------------------------------------*/
+
+/* --- @field_id@ --- *
+ *
+ * Arguments: @field *f@ = pointer to a field
+ * @mp *d@ = a destination element
+ * @mp *x@ = a source element
+ *
+ * Returns: The result element.
+ *
+ * Use: An identity operation which can be used if your field has no
+ * internal representation.
+ */
+
+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@ --- *
+ *
+ * Arguments: @mp *p@ = the characteristic of the field
+ *
+ * Returns: A pointer to the field.
+ *
+ * Use: Creates a field structure for a prime field of size %$p$%,
+ * using Montgomery reduction for arithmetic.
+ */
+
+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 %$\gf{2}$%
+ *
+ * Returns: A pointer to the field.
+ *
+ * Use: Creates a field structure for a binary field using naive
+ * arithmetic.
+ */
+
+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
+ }
+#endif
+
+#endif
projects / u / mdw / catacomb / blobdiff