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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: mgf.h,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The MGF mask generation function |
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 | |
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30 | /*----- Notes on the MGF-1 mask generating function -----------------------* |
31 | * |
32 | * The idea of a mask-generating function is that given an input of arbitrary |
33 | * size, it can emit a pseudorandom output `mask' of arbitrary size. This is |
34 | * used in PKCS#1 OAEP (RFC2437). My recommendation would be to use a decent |
35 | * stream cipher instead, like RC4 or SEAL. MGF-1 isn't very fast. |
36 | */ |
37 | |
38 | #ifndef CATACOMB_MGF_H |
39 | #define CATACOMB_MGF_H |
40 | |
41 | #ifdef __cplusplus |
42 | extern "C" { |
43 | #endif |
44 | |
45 | /*----- Header files ------------------------------------------------------*/ |
46 | |
47 | #include <mLib/bits.h> |
48 | |
49 | #ifndef CATACOMB_GCIPHER_H |
50 | # include "gcipher.h" |
51 | #endif |
52 | |
53 | #ifndef CATACOMB_GRAND_H |
54 | # include "grand.h" |
55 | #endif |
56 | |
57 | /*----- Macros ------------------------------------------------------------*/ |
58 | |
59 | #define MGF_DECL(PRE, pre) \ |
60 | \ |
61 | /* --- An MGF generation context --- */ \ |
62 | \ |
63 | typedef struct pre##_mgfctx { \ |
64 | pre##_ctx k; /* Underlying key context */ \ |
65 | uint32 c; /* Counter */ \ |
66 | octet buf[PRE##_HASHSZ]; /* Output buffer */ \ |
67 | size_t bsz; /* Size of buffered data */ \ |
68 | } pre##_mgfctx; \ |
69 | \ |
70 | /* --- Other useful constants --- */ \ |
71 | \ |
72 | extern const octet pre##_mgfkeysz[]; \ |
73 | \ |
74 | /* --- @pre_mgfkeybegin@, @pre_mgfkeyadd@ --- * \ |
75 | * \ |
76 | * Arguments: @pre_mgfctx *k@ = pointer to context to initialize \ |
77 | * @const void *p@ = pointer to data to contribute \ |
78 | * @size_t sz@ = size of data to contribute \ |
79 | * \ |
80 | * Returns: --- \ |
81 | * \ |
82 | * Use: A multi-step keying procedure for initializing an MGF \ |
83 | * context. The data is contributed to a hashing context \ |
84 | * which is then used for mask generation. If you only \ |
85 | * have a fixed buffer, you can save a lot of effort by \ |
86 | * simply calling @pre_mgfinit@. \ |
87 | */ \ |
88 | \ |
89 | extern void pre##_mgfkeybegin(pre##_mgfctx */*k*/); \ |
90 | extern void pre##_mgfkeyadd(pre##_mgfctx */*k*/, \ |
91 | const void */*p*/, size_t /*sz*/); \ |
92 | \ |
93 | /* ---- @pre_mgfinit@ --- * \ |
94 | * \ |
95 | * Arguments: @pre_mgfctx *k@ = pointer to context to initialize \ |
96 | * @const void *p@ = pointer to data to contribute \ |
97 | * @size_t sz@ = size of data to contribute \ |
98 | * \ |
99 | * Returns: --- \ |
100 | * \ |
101 | * Use: A simpler interface to initialization if all of your \ |
102 | * keying material is in one place. \ |
103 | */ \ |
104 | \ |
105 | extern void pre##_mgfinit(pre##_mgfctx */*k*/, \ |
106 | const void */*p*/, size_t /*sz*/); \ |
107 | \ |
108 | /* --- @pre_mgfencrypt@ --- * \ |
109 | * \ |
110 | * Arguments: @pre_mgfctx *k@ = pointer to masking context \ |
111 | * @const void *s@ = pointer to source buffer \ |
112 | * @void *d@ = pointer to destination buffer \ |
113 | * @size_t sz@ = size of buffers \ |
114 | * \ |
115 | * Returns: --- \ |
116 | * \ |
117 | * Use: Outputs pseudorandom data, or masks an input buffer. \ |
118 | * \ |
119 | * If @s@ is nonzero, the source material is exclusive- \ |
120 | * orred with the generated mask. If @d@ is zero, the \ |
121 | * generator is simply spun around for a while, which \ |
122 | * isn't very useful. \ |
123 | */ \ |
124 | \ |
125 | extern void pre##_mgfencrypt(pre##_mgfctx */*k*/, const void */*s*/, \ |
126 | void */*d*/, size_t /*sz*/); \ |
127 | \ |
128 | /* --- @pre_mgfsetindex@ --- * \ |
129 | * \ |
130 | * Arguments: @pre_mgfctx *k@ = pointer to masking context \ |
131 | * @uint32 *c@ = new index to set \ |
132 | * \ |
133 | * Returns: --- \ |
134 | * \ |
135 | * Use: Sets a new index. This may be used to step around the \ |
136 | * output stream in a rather crude way. \ |
137 | */ \ |
138 | \ |
139 | extern void pre##_mgfsetindex(pre##_mgfctx */*k*/, uint32 /*c*/); \ |
140 | \ |
141 | /* --- @pre_mgfrand@ --- * \ |
142 | * \ |
143 | * Arguments: @const void *k@ = pointer to key material \ |
144 | * @size_t sz@ = size of key material \ |
145 | * \ |
146 | * Returns: Pointer to a generic random number generator instance. \ |
147 | * \ |
148 | * Use: Creates a random number interface wrapper around an \ |
149 | * MGF-1-mode hash function. \ |
150 | */ \ |
151 | \ |
152 | extern grand *pre##_mgfrand(const void */*k*/, size_t /*sz*/); \ |
153 | \ |
154 | /* --- Generic cipher interface --- */ \ |
155 | \ |
156 | extern const gccipher pre##_mgf; |
157 | |
158 | /*----- That's all, folks -------------------------------------------------*/ |
159 | |
160 | #ifdef __cplusplus |
161 | } |
162 | #endif |
163 | |
164 | #endif |