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e6e0e332 MW |
1 | /* -*-c-*- |
2 | * | |
3 | * $Id: sac.c,v 1.1 2000/05/21 11:28:30 mdw Exp $ | |
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 | |
33 | * NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, | |
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 $ | |
52 | * Revision 1.1 2000/05/21 11:28:30 mdw | |
53 | * Initial check-in. | |
54 | * | |
55 | */ | |
56 | ||
57 | /*----- Header files ------------------------------------------------------*/ | |
58 | ||
59 | #include <math.h> | |
60 | #include <stdio.h> | |
61 | #include <stdlib.h> | |
62 | ||
63 | #include "bits.h" | |
64 | ||
65 | #include "fibrand.h" | |
66 | #include "matrix.h" | |
67 | #include "storin-tab.h" | |
68 | ||
69 | /*----- Static variables --------------------------------------------------*/ | |
70 | ||
71 | static fibrand r; | |
72 | ||
73 | /*----- The constant matrix -----------------------------------------------*/ | |
74 | ||
75 | static const uint24 m[] = STORIN_M; | |
76 | ||
77 | /*----- Magic numbers -----------------------------------------------------*/ | |
78 | ||
79 | #define PROBES 16384 | |
80 | #define ROUNDS 3 | |
81 | #define ROT(x) ((x) ^ ((x) >> 12)) | |
82 | /* #define ROT(x) ROL24(x, 7) */ | |
83 | ||
84 | /*----- Main code ---------------------------------------------------------*/ | |
85 | ||
86 | static octet w[256]; | |
87 | ||
88 | #define HAMWEIGHT(x) (w[U8((x) >> 16)] + w[U8((x) >> 8)] + w[U8(x)]) | |
89 | ||
90 | static void haminit(void) { | |
91 | unsigned i; | |
92 | for (i = 0; i < 256; i++) { | |
93 | unsigned ww = 0; | |
94 | unsigned j; | |
95 | for (j = 0; j < 8; j++) { | |
96 | if (i & (1 << j)) | |
97 | ww++; | |
98 | } | |
99 | w[i] = ww; | |
100 | } | |
101 | } | |
102 | ||
103 | static void eblk(uint24 *x) | |
104 | { | |
105 | uint24 t[4]; | |
106 | unsigned i, j; | |
107 | ||
108 | for (i = 0; i < ROUNDS; i++) { | |
109 | /* No key mixing */ | |
110 | matmul(t, m, x, 4, 4, 1); | |
111 | for (j = 0; j < 4; j++) | |
112 | x[j] = ROT(t[j]); | |
113 | } | |
114 | } | |
115 | ||
116 | typedef struct stats { | |
117 | double sx; | |
118 | double sx2; | |
119 | double n; | |
120 | } stats; | |
121 | ||
122 | static void probe(unsigned bit, uint24 *delta, struct stats *ps) | |
123 | { | |
124 | uint24 x[4], y[4]; | |
125 | unsigned i, j; | |
126 | struct stats s = { 0, 0, 0 }; | |
127 | ||
128 | for (i = 0; i < PROBES; i++) { | |
129 | unsigned h; | |
130 | for (j = 0; j < 4; j++) { | |
131 | x[j] = U24(fibrand_step(&r)); | |
132 | y[j] = x[j] ^ delta[j]; | |
133 | } | |
134 | eblk(x); | |
135 | eblk(y); | |
136 | h = 0; | |
137 | for (j = 0; j < 4; j++) { | |
138 | uint24 ww = x[j] ^ y[j]; | |
139 | h += HAMWEIGHT(ww); | |
140 | } | |
141 | /* printf("%06x %06x %06x %06x -> %06x %06x %06x %06x\n", */ | |
142 | /* delta[0], delta[1], delta[2], delta[3], */ | |
143 | /* x[0] ^ y[0], x[1] ^ y[1], x[2] ^ y[2], x[3] ^ y[3]); */ | |
144 | s.sx += h; ps->sx += h; | |
145 | s.sx2 += h * h; ps->sx2 += h * h; | |
146 | s.n++; ps->n++; | |
147 | } | |
148 | ||
149 | { | |
150 | double mean = s.sx / s.n; | |
151 | double var = s.sx2 / s.n - mean * mean; | |
152 | printf("bit %u: mean = %g, sd = %g\n", bit, mean, sqrt(var)); | |
153 | } | |
154 | } | |
155 | ||
156 | int main(void) | |
157 | { | |
158 | uint24 delta[4] = { 0 }; | |
159 | unsigned i; | |
160 | struct stats s = { 0, 0, 0 }; | |
161 | double mean, var; | |
162 | ||
163 | haminit(); | |
164 | fibrand_lcseed(&r, 0); | |
165 | ||
166 | for (i = 0; i < 96; i++) { | |
167 | uint24 *dd = delta + i / 24; | |
168 | uint24 m = 1 << (i % 24); | |
169 | *dd ^= m; | |
170 | probe(i, delta, &s); | |
171 | *dd ^= m; | |
172 | } | |
173 | ||
174 | mean = s.sx / s.n; | |
175 | var = s.sx2 / s.n - mean * mean; | |
176 | printf("\nsummary: mean = %g, sd = %g\n", mean, sqrt(var)); | |
177 | ||
178 | return (0); | |
179 | } | |
180 | ||
181 | /*----- That's all, folks -------------------------------------------------*/ |