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1 | /* -*-c-*- |
2 | * | |
6b2d9d76 | 3 | * $Id: dsarand.h,v 1.2 2000/07/02 15:21:20 mdw Exp $ |
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4 | * |
5 | * Random number generator for DSA | |
6 | * | |
7 | * (c) 1999 Straylight/Edgeware | |
8 | * (c) 2000 Mark Wooding | |
9 | */ | |
10 | ||
11 | /*----- Licensing notice --------------------------------------------------* | |
12 | * | |
13 | * Copyright (c) 2000 Mark Wooding | |
14 | * All rights reserved. | |
15 | * | |
16 | * Redistribution and use in source and binary forms, with or without | |
17 | * modification, are permitted provided that the following conditions are | |
18 | * met: | |
19 | * | |
20 | * 1. Redistributions of source code must retain the above copyright | |
21 | * notice, this list of conditions and the following disclaimer. | |
22 | * | |
23 | * 2, Redistributions in binary form must reproduce the above copyright | |
24 | * notice, this list of conditions and the following disclaimer in the | |
25 | * documentation and/or other materials provided with the distribution. | |
26 | * | |
27 | * 3. The name of the authors may not be used to endorse or promote | |
28 | * products derived from this software without specific prior written | |
29 | * permission. | |
30 | * | |
31 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
32 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
33 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN | |
6b2d9d76 | 34 | * NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
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35 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
36 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
37 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
40 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
41 | * POSSIBILITY OF SUCH DAMAGE. | |
42 | * | |
43 | * Instead of accepting the above terms, you may redistribute and/or modify | |
44 | * this software under the terms of either the GNU General Public License, | |
45 | * or the GNU Library General Public License, published by the Free | |
46 | * Software Foundation; either version 2 of the License, or (at your | |
47 | * option) any later version. | |
48 | */ | |
49 | ||
50 | /*----- Revision history --------------------------------------------------* | |
51 | * | |
52 | * $Log: dsarand.h,v $ | |
6b2d9d76 MW |
53 | * Revision 1.2 2000/07/02 15:21:20 mdw |
54 | * Fix licence text. | |
55 | * | |
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56 | * Revision 1.1 2000/05/21 11:28:30 mdw |
57 | * Initial check-in. | |
58 | * | |
59 | * --- Past lives (Catacomb) --- * | |
60 | * | |
61 | * Revision 1.1 1999/12/22 15:53:12 mdw | |
62 | * Random number generator for finding DSA parameters. | |
63 | * | |
64 | */ | |
65 | ||
66 | #ifndef DSARAND_H | |
67 | #define DSARAND_H | |
68 | ||
69 | #ifdef __cplusplus | |
70 | extern "C" { | |
71 | #endif | |
72 | ||
73 | /*----- Header files ------------------------------------------------------*/ | |
74 | ||
75 | #ifndef BITS_H | |
76 | # include "bits.h" | |
77 | #endif | |
78 | ||
79 | #ifndef SHA_H | |
80 | # include "sha.h" | |
81 | #endif | |
82 | ||
83 | /*----- Data structures ---------------------------------------------------*/ | |
84 | ||
85 | typedef struct dsarand { | |
86 | octet *p; /* Pointer to seed (modified) */ | |
87 | size_t sz; /* Size of the seed buffer */ | |
88 | unsigned passes; /* Number of passes to make */ | |
89 | } dsarand; | |
90 | ||
91 | /*----- Functions provided ------------------------------------------------*/ | |
92 | ||
93 | /* --- @dsarand_init@ --- * | |
94 | * | |
95 | * Arguments: @dsarand *d@ = pointer to context | |
96 | * @const void *p@ = pointer to seed buffer | |
97 | * @size_t sz@ = size of the buffer | |
98 | * | |
99 | * Returns: --- | |
100 | * | |
101 | * Use: Initializes a DSA random number generator. | |
102 | */ | |
103 | ||
104 | extern void dsarand_init(dsarand */*d*/, const void */*p*/, size_t /*sz*/); | |
105 | ||
106 | /* --- @dsarand_reseed@ --- * | |
107 | * | |
108 | * Arguments: @dsarand *d@ = pointer to context | |
109 | * @const void *p@ = pointer to seed buffer | |
110 | * @size_t sz@ = size of the buffer | |
111 | * | |
112 | * Returns: --- | |
113 | * | |
114 | * Use: Initializes a DSA random number generator. | |
115 | */ | |
116 | ||
117 | extern void dsarand_reseed(dsarand */*d*/, const void */*p*/, size_t /*sz*/); | |
118 | ||
119 | /* --- @dsarand_destroy@ --- * | |
120 | * | |
121 | * Arguments: @dsarand *d@ = pointer to context | |
122 | * | |
123 | * Returns: --- | |
124 | * | |
125 | * Use: Disposes of a DSA random number generation context. | |
126 | */ | |
127 | ||
128 | extern void dsarand_destroy(dsarand */*d*/); | |
129 | ||
130 | /* --- @dsarand_fill@ --- * | |
131 | * | |
132 | * Arguments: @dsarand *d@ = pointer to context | |
133 | * @void *p@ = pointer to output buffer | |
134 | * @size_t sz@ = size of output buffer | |
135 | * | |
136 | * Returns: --- | |
137 | * | |
138 | * Use: Fills an output buffer with pseudorandom data. | |
139 | * | |
140 | * Let %$p$% be the numerical value of the input buffer, and let | |
141 | * %$b$% be the number of bytes required. Let | |
142 | * %$z = \lceil b / 20 \rceil$% be the number of SHA outputs | |
143 | * required. Then the output of pass %$n$% is | |
144 | * | |
145 | * %$P_n = \sum_{0 \le i < z} 2^{160i} SHA(p + nz + i)$% | |
146 | * %${} \bmod 2^{8b}$% | |
147 | * | |
148 | * and the actual result in the output buffer is the XOR of all | |
149 | * of the output passes. | |
150 | * | |
151 | * The DSA procedure for choosing @q@ involves two passes with | |
152 | * %$z = 1$%; the procedure for choosing @p@ involves one pass | |
153 | * with larger %$z$%. This generalization of the DSA generation | |
154 | * procedure is my own invention but it seems relatively sound. | |
155 | */ | |
156 | ||
157 | extern void dsarand_fill(dsarand */*d*/, void */*p*/, size_t /*sz*/); | |
158 | ||
159 | /*----- That's all, folks -------------------------------------------------*/ | |
160 | ||
161 | #ifdef __cplusplus | |
162 | } | |
163 | #endif | |
164 | ||
165 | #endif |