X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/keysz-conv.c

diff --git a/keysz-conv.c b/keysz-conv.c
deleted file mode 100644
index 2d40558..0000000
--- a/keysz-conv.c
+++ /dev/null
@@ -1,179 +0,0 @@
-/* -*-c-*-
- *
- * Key length conversions
- *
- * (c) 2007 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.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <math.h>
-
-#include "keysz.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- Primitive conversions --- */
-
-static double fromnfs(double nbits)
-{
-  /* --- Magic taken from P1363 --- */
-#define LOG2 0.6931471805599453094172321214581765680755
-#define MAGIC 8.567936			/* = 17.135872 / 2 */
-  double z = log(nbits * LOG2)/LOG2;
-  return 4.0/3.0 * pow(3 * nbits * z*z, 1.0/3.0) - MAGIC;
-}
-
-static double tonfs(double nbits)
-{
-  double hi, lo, mid, val;
-
-  /* --- Find upper and lower bounds --- */
-
-  for (hi = nbits; fromnfs(hi) < nbits; hi *= 2);
-  for (lo = nbits; fromnfs(lo) > nbits; lo /= 2);
-
-  /* --- Bisect the interval until we get an answer --- */
-
-#define THRESH 0.01
-  for (;;) {
-    mid = (hi + lo)/2;
-    val = fromnfs(mid);
-    if (fabs(val - nbits) < THRESH)
-      return (mid);
-    else if (val < nbits)
-      lo = mid;
-    else
-      hi = mid;
-  }
-}
-
-static double torho(double nbits) { return 2*nbits; }
-static double fromrho(double nbits) { return nbits/2; }
-
-/* --- @keysz_fromdl@, @_fromschnorr@, @_fromif@, @_fromec@ --- *
- *
- * Arguments:	@double nbits@ = key size
- *
- * Returns:	Equivalent symmetric key size.
- *
- * Use:		Converts key lengths of various kinds of reference problems
- *		to (roughly) equivalent symmetric key sizes.
- *
- *		  * Given the bit length of %$p$%, @keysz_fromdl@ returns a
- *		    key size representing the difficulty of computing
- *		    discrete logarithms in %$\gf{p}$%, for %$p$% prime or a
- *		    small power of a prime.
- *
- *		  * Given the bit length of %$r$%, @keysz_fromschnorr@
- *		    returns a key size representing the difficulty of
- *		    computing discrete logarithms in a subgroup of %$\gf{q}$%
- *		    of order %$r$%.
- *
- *		  * Given the bit length of %$n$%, @keysz_fromif@ returns a
- *		    key size representing the difficulty of factoring a
- *		    `hard' number %$n = p q$%, where %$p$% and %$q$% are
- *		    primes of (near enough) the same length.
- *
- *		  * Given the bit length of %$r$%, @keysz_fromec@ returns a
- *		    key size representing the difficulty of computing
- *		    discrete logarithms in a subgroup of order-%$r$% of an
- *		    elliptic curve over a finite field.
- *
- *		These functions take and return @double@ rather than an
- *		integer type in order to preserve precision between
- *		conversions.
- */
-
-#define CONVERSIONS(_)							\
-  _(dl, nfs)								\
-  _(schnorr, rho)							\
-  _(if, nfs)								\
-  _(ec, rho)
-
-#define DEFINE_FROM(what, how)						\
-  double keysz_from##what(double nbits) { return from##how(nbits); }
-
-CONVERSIONS(DEFINE_FROM)
-
-/* --- @keysz_todl@, @_toschnorr@, @_toif@, @_toec@ --- *
- *
- * Arguments:	@unsigned long nbits@ = symmetric key size
- *
- * Returns:	Equivalent key size.
- *
- * Use:		Converts symmetric key sizes to (roughly) equivalent key
- *		sizes for various kinds of reference problems.  These are the
- *		approximate inverses of the functions above.
- */
-
-#define DEFINE_TO(what, how)						\
-  double keysz_to##what(double nbits) { return to##how(nbits); }
-
-CONVERSIONS(DEFINE_TO)
-
-/*----- Interactive mode for testing --------------------------------------*/
-
-#ifdef TEST_RIG
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-static const struct entry {
-  const char *name;
-  double (*func)(double);
-} tab[] = {
-#define ENTRY_FROM(what, how) { "from" #what, keysz_from##what },
-#define ENTRY_TO(what, how) { "to" #what, keysz_to##what },
-  CONVERSIONS(ENTRY_FROM)
-  CONVERSIONS(ENTRY_TO)
-  { 0 }
-};
-
-int main(int argc, char *argv[])
-{
-  const struct entry *e;
-  double d;
-
-  if (!argv[1]) {
-    fprintf(stderr, "conversions:");
-    for (e = tab; e->name; e++) fprintf(stderr, " %s", e->name);
-    putc('\n', stderr);
-    return (1);
-  }
-  for (e = tab; e->name && strcmp(e->name, argv[1]); e++);
-  if (!e) {
-    fprintf(stderr, "unknown conversion `%s'\n", argv[1]);
-    return (1);
-  }
-  for (argv += 2; *argv; argv++) {
-    d = strtod(*argv, 0);
-    printf("%s(%g) = %g\n", e->name, d, e->func(d));
-  }
-  return (0);
-}
-
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/