chiark / gitweb /
Version bump.
[storin] / sac.c
CommitLineData
e6e0e332
MW
1/* -*-c-*-
2 *
6b2d9d76 3 * $Id: sac.c,v 1.2 2000/07/02 15:21:20 mdw Exp $
e6e0e332
MW
4 *
5 * Testing for strict avalanche
6 *
7 * (c) 2000 Mark Wooding
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * Copyright (c) 2000 Mark Wooding
13 * All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions are
17 * met:
18 *
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 *
22 * 2, Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * 3. The name of the authors may not be used to endorse or promote
27 * products derived from this software without specific prior written
28 * permission.
29 *
30 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
31 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
32 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
6b2d9d76 33 * NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
e6e0e332
MW
34 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
35 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
36 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
38 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
39 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
40 * POSSIBILITY OF SUCH DAMAGE.
41 *
42 * Instead of accepting the above terms, you may redistribute and/or modify
43 * this software under the terms of either the GNU General Public License,
44 * or the GNU Library General Public License, published by the Free
45 * Software Foundation; either version 2 of the License, or (at your
46 * option) any later version.
47 */
48
49/*----- Revision history --------------------------------------------------*
50 *
51 * $Log: sac.c,v $
6b2d9d76
MW
52 * Revision 1.2 2000/07/02 15:21:20 mdw
53 * Fix licence text.
54 *
e6e0e332
MW
55 * Revision 1.1 2000/05/21 11:28:30 mdw
56 * Initial check-in.
57 *
58 */
59
60/*----- Header files ------------------------------------------------------*/
61
62#include <math.h>
63#include <stdio.h>
64#include <stdlib.h>
65
66#include "bits.h"
67
68#include "fibrand.h"
69#include "matrix.h"
70#include "storin-tab.h"
71
72/*----- Static variables --------------------------------------------------*/
73
74static fibrand r;
75
76/*----- The constant matrix -----------------------------------------------*/
77
78static const uint24 m[] = STORIN_M;
79
80/*----- Magic numbers -----------------------------------------------------*/
81
82#define PROBES 16384
83#define ROUNDS 3
84#define ROT(x) ((x) ^ ((x) >> 12))
85/* #define ROT(x) ROL24(x, 7) */
86
87/*----- Main code ---------------------------------------------------------*/
88
89static octet w[256];
90
91#define HAMWEIGHT(x) (w[U8((x) >> 16)] + w[U8((x) >> 8)] + w[U8(x)])
92
93static void haminit(void) {
94 unsigned i;
95 for (i = 0; i < 256; i++) {
96 unsigned ww = 0;
97 unsigned j;
98 for (j = 0; j < 8; j++) {
99 if (i & (1 << j))
100 ww++;
101 }
102 w[i] = ww;
103 }
104}
105
106static void eblk(uint24 *x)
107{
108 uint24 t[4];
109 unsigned i, j;
110
111 for (i = 0; i < ROUNDS; i++) {
112 /* No key mixing */
113 matmul(t, m, x, 4, 4, 1);
114 for (j = 0; j < 4; j++)
115 x[j] = ROT(t[j]);
116 }
117}
118
119typedef struct stats {
120 double sx;
121 double sx2;
122 double n;
123} stats;
124
125static void probe(unsigned bit, uint24 *delta, struct stats *ps)
126{
127 uint24 x[4], y[4];
128 unsigned i, j;
129 struct stats s = { 0, 0, 0 };
130
131 for (i = 0; i < PROBES; i++) {
132 unsigned h;
133 for (j = 0; j < 4; j++) {
134 x[j] = U24(fibrand_step(&r));
135 y[j] = x[j] ^ delta[j];
136 }
137 eblk(x);
138 eblk(y);
139 h = 0;
140 for (j = 0; j < 4; j++) {
141 uint24 ww = x[j] ^ y[j];
142 h += HAMWEIGHT(ww);
143 }
144/* printf("%06x %06x %06x %06x -> %06x %06x %06x %06x\n", */
145/* delta[0], delta[1], delta[2], delta[3], */
146/* x[0] ^ y[0], x[1] ^ y[1], x[2] ^ y[2], x[3] ^ y[3]); */
147 s.sx += h; ps->sx += h;
148 s.sx2 += h * h; ps->sx2 += h * h;
149 s.n++; ps->n++;
150 }
151
152 {
153 double mean = s.sx / s.n;
154 double var = s.sx2 / s.n - mean * mean;
155 printf("bit %u: mean = %g, sd = %g\n", bit, mean, sqrt(var));
156 }
157}
158
159int main(void)
160{
161 uint24 delta[4] = { 0 };
162 unsigned i;
163 struct stats s = { 0, 0, 0 };
164 double mean, var;
165
166 haminit();
167 fibrand_lcseed(&r, 0);
168
169 for (i = 0; i < 96; i++) {
170 uint24 *dd = delta + i / 24;
171 uint24 m = 1 << (i % 24);
172 *dd ^= m;
173 probe(i, delta, &s);
174 *dd ^= m;
175 }
176
177 mean = s.sx / s.n;
178 var = s.sx2 / s.n - mean * mean;
179 printf("\nsummary: mean = %g, sd = %g\n", mean, sqrt(var));
180
181 return (0);
182}
183
184/*----- That's all, folks -------------------------------------------------*/