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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: hmac.h,v 1.2 1999/12/10 23:17:39 mdw Exp $ |
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4 | * |
5 | * Generic code for HMAC and NMAC |
6 | * |
7 | * (c) 1998 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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: hmac.h,v $ |
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33 | * Revision 1.2 1999/12/10 23:17:39 mdw |
34 | * Split mode macros into interface and implementation. |
35 | * |
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36 | * Revision 1.1 1999/09/03 08:41:12 mdw |
37 | * Initial import. |
38 | * |
39 | */ |
40 | |
41 | /*----- Notes on the HMAC and NMAC constructions --------------------------* |
42 | * |
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43 | * Designed by Mihir Bellare, Ran Canetti and Hugo Krawczyk, NMAC is a method |
44 | * for constructing keyed message authentication algorithms from unkeyed hash |
45 | * functions. It has been proven to provide useful security given reasonable |
46 | * assumptions about the underlying hash function. HMAC is an alternative |
47 | * formulation which doesn't require low-level access to the hash function's |
48 | * implementation. NMAC was designed to allow MD5 has a suitable underlying |
49 | * hash function, even though doubts were already being raised about its |
50 | * collision resistance. |
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51 | */ |
52 | |
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53 | #ifndef CATACOMB_HMAC_H |
54 | #define CATACOMB_HMAC_H |
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55 | |
56 | #ifdef __cplusplus |
57 | extern "C" { |
58 | #endif |
59 | |
60 | /*----- Header files ------------------------------------------------------*/ |
61 | |
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62 | #include <stddef.h> |
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63 | |
64 | #include <mLib/bits.h> |
65 | |
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66 | #ifndef CATACOMB_GMAC_H |
67 | # include "gmac.h" |
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68 | #endif |
69 | |
70 | /*----- Macros ------------------------------------------------------------*/ |
71 | |
72 | /* --- @HMAC_DECL@ --- * |
73 | * |
74 | * Arguments: @PRE@, @pre@ = prefixes for the underlying hash function |
75 | * |
76 | * Use: Creates declarations for the HMAC and NMAC functions. |
77 | */ |
78 | |
79 | #define HMAC_DECL(PRE, pre) \ |
80 | \ |
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81 | /* --- An HMAC or NMAC key --- */ \ |
82 | \ |
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83 | typedef struct pre##_mackey { \ |
84 | octet ochain[PRE##_HASHSZ]; /* Chaining for outer hash */ \ |
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85 | unsigned ocount; /* Byte count for outer hash */ \ |
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86 | octet ichain[PRE##_HASHSZ]; /* Chaining for inner hash */ \ |
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87 | unsigned icount; /* Byte count for inner hash */ \ |
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88 | } pre##_mackey; \ |
89 | \ |
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90 | /* --- An HMAC or NMAC hashing context --- */ \ |
91 | \ |
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92 | typedef struct pre##_macctx { \ |
93 | pre##_ctx ctx; /* Context for main hashing */ \ |
94 | octet chain[PRE##_HASHSZ]; /* Chaining for outer hash */ \ |
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95 | unsigned count; /* Byte count for outer hash */ \ |
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96 | } pre##_macctx; \ |
97 | \ |
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98 | /* --- @pre_nmacinit@ --- * \ |
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99 | * \ |
100 | * Arguments: @pre_macctx *key@ = pointer to a MAC key object \ |
101 | * @const void *ok@ = pointer to outer hash init vector \ |
102 | * @const void *ik@ = pointer to inner hash init vector \ |
103 | * \ |
104 | * Returns: --- \ |
105 | * \ |
106 | * Use: Initializes a MAC key for doing NMAC hashing. \ |
107 | */ \ |
108 | \ |
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109 | extern void pre##_nmacinit(pre##_mackey */*key*/, \ |
110 | const void */*ok*/, const void */*ik*/); \ |
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111 | \ |
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112 | /* --- @pre_hmacinit@ --- * \ |
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113 | * \ |
114 | * Arguments: @pre_mackey *key@ = pointer to MAC key object \ |
115 | * @const void *k@ = pointer to key to use \ |
116 | * @size_t sz@ = size of key data \ |
117 | * \ |
118 | * Returns: --- \ |
119 | * \ |
120 | * Use: Initializes a MAC key for doing HMAC hashing. Keys \ |
121 | * longer than the hash function's output size aren't very \ |
122 | * useful, but are accepted. Keys longer than the hash's \ |
123 | * block size are also accepted; they are hashed before \ |
124 | * use, as specified in RFC2104. \ |
125 | */ \ |
126 | \ |
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127 | extern void pre##_hmacinit(pre##_mackey */*key*/, \ |
128 | const void */*k*/, size_t /*sz*/); \ |
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129 | \ |
130 | /* --- @pre_macinit@ --- * \ |
131 | * \ |
132 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
133 | * @const pre_mackey *key@ = pointer to MAC key block \ |
134 | * \ |
135 | * Returns: --- \ |
136 | * \ |
137 | * Use: Instantiates a MAC context from a key block. \ |
138 | */ \ |
139 | \ |
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140 | extern void pre##_macinit(pre##_macctx */*ctx*/, \ |
141 | const pre##_mackey */*key*/); \ |
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142 | \ |
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143 | /* --- @pre_machash@ --- * \ |
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144 | * \ |
145 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
146 | * @const void *buf@ = pointer to buffer \ |
147 | * @size_t sz@ = size of the buffer \ |
148 | * \ |
149 | * Returns: --- \ |
150 | * \ |
151 | * Use: Hashes a buffer. \ |
152 | */ \ |
153 | \ |
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154 | extern void pre##_machash(pre##_macctx */*ctx*/, \ |
155 | const void */*buf*/, size_t /*sz*/); \ |
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156 | \ |
157 | /* --- @pre_macdone@ --- * \ |
158 | * \ |
159 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
160 | * @void *mac@ = pointer to buffer to receive MAC \ |
161 | * \ |
162 | * Returns: --- \ |
163 | * \ |
164 | * Use: Returns the result of a MAC computation. \ |
165 | */ \ |
166 | \ |
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167 | extern void pre##_macdone(pre##_macctx */*ctx*/, void */*mac*/); \ |
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168 | \ |
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169 | /* --- Generic MAC interface --- */ \ |
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170 | \ |
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171 | extern const gcmac pre##_hmac; |
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172 | |
173 | /*----- That's all, folks -------------------------------------------------*/ |
174 | |
175 | #ifdef __cplusplus |
176 | } |
177 | #endif |
178 | |
179 | #endif |