X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/math/limlee.h

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+/* -*-c-*-
+ *
+ * Generate Lim-Lee primes
+ *
+ * (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_LIMLEE_H
+#define CATACOMB_LIMLEE_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_PGEN_H
+#  include "pgen.h"
+#endif
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct limlee_factor {
+  mp *p;				/* The actual prime */
+  unsigned tag;				/* A tag, usable by the generator */
+  void *more;				/* Pointer to more data */
+} limlee_factor;
+
+typedef struct limlee_stepctx {
+
+  /* --- To be initialized by the caller --- */
+
+  unsigned f;				/* Various useful flags */
+  mp *newp;				/* Initial valid for new primes */
+  unsigned ql, pl;			/* Size of factors and result */
+  const struct limlee_primeops *pops;	/* Pointer to generator ops */
+  void *pc;				/* Context ptr for generator ops */
+  pgen_proc *iev;			/* Event handler for inner @pgen@ */
+  void *iec;				/* Context for inner @pgen@ */
+  grand *r;				/* Random number generator */
+
+  /* --- Output values --- */
+
+  size_t nf;				/* Number of factors wanted */
+  limlee_factor *v;			/* Vector of factors */
+
+  /* --- Maintained internally --- */
+
+  octet *c;				/* Combination byte-flag vector */
+  unsigned long seq;			/* Sequence number for primes */
+  size_t poolsz;			/* Size of the small-prime pool */
+  dstr d;				/* String for subprime name */
+  limlee_factor qq;			/* Big prime to pick up slack */
+
+} limlee_stepctx;
+
+typedef struct limlee_primeops {
+  void (*pgen)(limlee_factor */*f*/, unsigned /*pl*/, limlee_stepctx */*l*/);
+  void (*pfree)(limlee_factor */*f*/, limlee_stepctx */*l*/);
+} limlee_primeops;
+
+/* --- Flags --- */
+
+#define LIMLEE_KEEPFACTORS 1u
+
+/*----- The Lim-Lee stepper function --------------------------------------*/
+
+extern pgen_proc limlee_step;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @limlee@ --- *
+ *
+ * Arguments:	@const char *name@ = pointer to name root
+ *		@mp *d@ = pointer to destination integer
+ *		@mp *newp@ = how to generate factor primes
+ *		@unsigned ql@ = size of individual factors
+ *		@unsigned pl@ = size of large prime
+ *		@grand *r@ = a random number source
+ *		@unsigned on@ = number of outer attempts to make
+ *		@pgen_proc *oev@ = outer event handler function
+ *		@void *oec@ = argument for the outer event handler
+ *		@pgen_proc *iev@ = inner event handler function
+ *		@void *iec@ = argument for the inner event handler
+ *		@size_t *nf@, @mp ***f@ = output array for factors
+ *
+ * Returns:	A Lim-Lee prime, or null if generation failed.
+ *
+ * Use:		Generates Lim-Lee primes.  A Lim-Lee prime %$p$% is one which
+ *		satisfies %$p = 2 \prod_i q_i + 1$%, where all of the %$q_i$%
+ *		are large enough to resist square-root discrete log
+ *		algorithms.
+ *
+ *		If we succeed, and @f@ is non-null, we write the array of
+ *		factors chosen to @f@ for the benefit of the caller.
+ */
+
+extern mp *limlee(const char */*name*/, mp */*d*/, mp */*newp*/,
+		  unsigned /*ql*/, unsigned /*pl*/, grand */*r*/,
+		  unsigned /*on*/, pgen_proc */*oev*/, void */*oec*/,
+		  pgen_proc */*iev*/, void */*iec*/,
+		  size_t */*nf*/, mp ***/*f*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif