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1 | /* -*-c-*- |
2 | * | |
6b2d9d76 | 3 | * $Id: sac.c,v 1.2 2000/07/02 15:21:20 mdw Exp $ |
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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, |
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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 | ||
74 | static fibrand r; | |
75 | ||
76 | /*----- The constant matrix -----------------------------------------------*/ | |
77 | ||
78 | static 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 | ||
89 | static octet w[256]; | |
90 | ||
91 | #define HAMWEIGHT(x) (w[U8((x) >> 16)] + w[U8((x) >> 8)] + w[U8(x)]) | |
92 | ||
93 | static 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 | ||
106 | static 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 | ||
119 | typedef struct stats { | |
120 | double sx; | |
121 | double sx2; | |
122 | double n; | |
123 | } stats; | |
124 | ||
125 | static 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 | ||
159 | int 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 -------------------------------------------------*/ |