[u/mdw/catacomb] / gfshare-mktab.c

/* -*-c-*-
 *
 * $Id: gfshare-mktab.c,v 1.1 2000/06/17 10:56:30 mdw Exp $
 *
 * Generate tables for %$\gf(2^8)$% multiplication
 *
 * (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.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: gfshare-mktab.c,v $
 * Revision 1.1  2000/06/17 10:56:30  mdw
 * Fast but nonstandard secret sharing system.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>

#include <mLib/bits.h>

/*----- Magic numbers -----------------------------------------------------*/

#define MOD 0x11d

/*----- Main code ---------------------------------------------------------*/

int main(int argc, char *argv[])
{
  octet log[256], alog[256];
  unsigned x;
  unsigned i;

  x = 1;
  for (i = 0; i < 255; i++) {
    alog[i] = x;
    log[x] = i;
    x <<= 1;
    if (x & 0x100)
      x ^= MOD;
  }
  log[0] = 0;
  alog[255] = 1;

  fputs("\
/* -*-c-*-\n\
 *\n\
 * Log tables for secret sharing in %$\\gf(2^8)$% [generated]\n\
 */\n\
\n\
#ifndef GFSHARE_TAB_H\n\
#define GFSHARE_TAB_H\n\
\n\
#define GFSHARE_LOG {							\\\n\
  ", stdout);

  for (i = 0; i < 256; i++) {
    printf("0x%02x", log[i]);
    if (i == 255)
      puts("			\\\n}\n");
    else if (i % 8 == 7)
      fputs(",			\\\n  ", stdout);
    else
      fputs(", ", stdout);
  }

  fputs("\
#define GFSHARE_EXP {							\\\n\
  ", stdout);

  for (i = 0; i < 510; i++) {
    printf("0x%02x", alog[i % 255]);
    if (i == 509)
      puts("					\\\n}\n");
    else if (i % 8 == 7)
      fputs(",			\\\n  ", stdout);
    else
      fputs(", ", stdout);
  }

  /* --- Done --- */

  fputs("#endif\n", stdout);

  if (fclose(stdout)) {
    fprintf(stderr, "error writing data\n");
    exit(EXIT_FAILURE);
  }

  return (0);  
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
6c1035f5	1	/* --c--
	2	*
	3	* $Id: gfshare-mktab.c,v 1.1 2000/06/17 10:56:30 mdw Exp $
	4	*
	5	* Generate tables for %$\gf(2^8)$% multiplication
	6	*
	7	* (c) 2000 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of Catacomb.
	13	*
	14	* Catacomb is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
	18	*
	19	* Catacomb is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU Library General Public
	25	* License along with Catacomb; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
	30	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: gfshare-mktab.c,v $
	33	* Revision 1.1 2000/06/17 10:56:30 mdw
	34	* Fast but nonstandard secret sharing system.
	35	*
	36	*/
	37
	38	/----- Header files ------------------------------------------------------/
	39
	40	#include <stdio.h>
	41	#include <stdlib.h>
	42
	43	#include <mLib/bits.h>
	44
	45	/----- Magic numbers -----------------------------------------------------/
	46
	47	#define MOD 0x11d
	48
	49	/----- Main code ---------------------------------------------------------/
	50
	51	int main(int argc, char *argv[])
	52	{
	53	octet log[256], alog[256];
	54	unsigned x;
	55	unsigned i;
	56
	57	x = 1;
	58	for (i = 0; i < 255; i++) {
	59	alog[i] = x;
	60	log[x] = i;
	61	x <<= 1;
	62	if (x & 0x100)
	63	x ^= MOD;
	64	}
65	log[0] = 0;
66	alog[255] = 1;
67
68	fputs("\
69	/* --c--\n\
70	*\n\
71	* Log tables for secret sharing in %$\\gf(2^8)$% [generated]\n\
72	*/\n\
73	\n\
74	#ifndef GFSHARE_TAB_H\n\
75	#define GFSHARE_TAB_H\n\
76	\n\
77	#define GFSHARE_LOG { \\\n\
78	", stdout);
79
80	for (i = 0; i < 256; i++) {
81	printf("0x%02x", log[i]);
82	if (i == 255)
83	puts(" \\\n}\n");
84	else if (i % 8 == 7)
85	fputs(", \\\n ", stdout);
86	else
87	fputs(", ", stdout);
88	}
89
90	fputs("\
91	#define GFSHARE_EXP { \\\n\
92	", stdout);
93
94	for (i = 0; i < 510; i++) {
95	printf("0x%02x", alog[i % 255]);
96	if (i == 509)
97	puts(" \\\n}\n");
98	else if (i % 8 == 7)
99	fputs(", \\\n ", stdout);
100	else
101	fputs(", ", stdout);
102	}
103
104	/* --- Done --- */
105
106	fputs("#endif\n", stdout);
107
108	if (fclose(stdout)) {
109	fprintf(stderr, "error writing data\n");
110	exit(EXIT_FAILURE);
111	}
112
113	return (0);
114	}
115
116	/----- That's all, folks -------------------------------------------------/