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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: hmac.h,v 1.3 2000/06/17 11:23:57 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 1.3 2000/06/17 11:23:57 mdw |
34 | * New key size interface. |
35 | * |
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36 | * Revision 1.2 1999/12/10 23:17:39 mdw |
37 | * Split mode macros into interface and implementation. |
38 | * |
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39 | * Revision 1.1 1999/09/03 08:41:12 mdw |
40 | * Initial import. |
41 | * |
42 | */ |
43 | |
44 | /*----- Notes on the HMAC and NMAC constructions --------------------------* |
45 | * |
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46 | * Designed by Mihir Bellare, Ran Canetti and Hugo Krawczyk, NMAC is a method |
47 | * for constructing keyed message authentication algorithms from unkeyed hash |
48 | * functions. It has been proven to provide useful security given reasonable |
49 | * assumptions about the underlying hash function. HMAC is an alternative |
50 | * formulation which doesn't require low-level access to the hash function's |
51 | * implementation. NMAC was designed to allow MD5 has a suitable underlying |
52 | * hash function, even though doubts were already being raised about its |
53 | * collision resistance. |
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54 | */ |
55 | |
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56 | #ifndef CATACOMB_HMAC_H |
57 | #define CATACOMB_HMAC_H |
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58 | |
59 | #ifdef __cplusplus |
60 | extern "C" { |
61 | #endif |
62 | |
63 | /*----- Header files ------------------------------------------------------*/ |
64 | |
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65 | #include <stddef.h> |
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66 | |
67 | #include <mLib/bits.h> |
68 | |
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69 | #ifndef CATACOMB_GMAC_H |
70 | # include "gmac.h" |
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71 | #endif |
72 | |
73 | /*----- Macros ------------------------------------------------------------*/ |
74 | |
75 | /* --- @HMAC_DECL@ --- * |
76 | * |
77 | * Arguments: @PRE@, @pre@ = prefixes for the underlying hash function |
78 | * |
79 | * Use: Creates declarations for the HMAC and NMAC functions. |
80 | */ |
81 | |
82 | #define HMAC_DECL(PRE, pre) \ |
83 | \ |
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84 | /* --- An HMAC or NMAC key --- */ \ |
85 | \ |
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86 | typedef struct pre##_mackey { \ |
87 | octet ochain[PRE##_HASHSZ]; /* Chaining for outer hash */ \ |
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88 | unsigned ocount; /* Byte count for outer hash */ \ |
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89 | octet ichain[PRE##_HASHSZ]; /* Chaining for inner hash */ \ |
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90 | unsigned icount; /* Byte count for inner hash */ \ |
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91 | } pre##_mackey; \ |
92 | \ |
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93 | /* --- An HMAC or NMAC hashing context --- */ \ |
94 | \ |
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95 | typedef struct pre##_macctx { \ |
96 | pre##_ctx ctx; /* Context for main hashing */ \ |
97 | octet chain[PRE##_HASHSZ]; /* Chaining for outer hash */ \ |
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98 | unsigned count; /* Byte count for outer hash */ \ |
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99 | } pre##_macctx; \ |
100 | \ |
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101 | /* --- Other useful constants --- */ \ |
102 | \ |
103 | extern const octet pre##_mackeysz[]; \ |
104 | \ |
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105 | /* --- @pre_nmacinit@ --- * \ |
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106 | * \ |
107 | * Arguments: @pre_macctx *key@ = pointer to a MAC key object \ |
108 | * @const void *ok@ = pointer to outer hash init vector \ |
109 | * @const void *ik@ = pointer to inner hash init vector \ |
110 | * \ |
111 | * Returns: --- \ |
112 | * \ |
113 | * Use: Initializes a MAC key for doing NMAC hashing. \ |
114 | */ \ |
115 | \ |
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116 | extern void pre##_nmacinit(pre##_mackey */*key*/, \ |
117 | const void */*ok*/, const void */*ik*/); \ |
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118 | \ |
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119 | /* --- @pre_hmacinit@ --- * \ |
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120 | * \ |
121 | * Arguments: @pre_mackey *key@ = pointer to MAC key object \ |
122 | * @const void *k@ = pointer to key to use \ |
123 | * @size_t sz@ = size of key data \ |
124 | * \ |
125 | * Returns: --- \ |
126 | * \ |
127 | * Use: Initializes a MAC key for doing HMAC hashing. Keys \ |
128 | * longer than the hash function's output size aren't very \ |
129 | * useful, but are accepted. Keys longer than the hash's \ |
130 | * block size are also accepted; they are hashed before \ |
131 | * use, as specified in RFC2104. \ |
132 | */ \ |
133 | \ |
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134 | extern void pre##_hmacinit(pre##_mackey */*key*/, \ |
135 | const void */*k*/, size_t /*sz*/); \ |
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136 | \ |
137 | /* --- @pre_macinit@ --- * \ |
138 | * \ |
139 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
140 | * @const pre_mackey *key@ = pointer to MAC key block \ |
141 | * \ |
142 | * Returns: --- \ |
143 | * \ |
144 | * Use: Instantiates a MAC context from a key block. \ |
145 | */ \ |
146 | \ |
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147 | extern void pre##_macinit(pre##_macctx */*ctx*/, \ |
148 | const pre##_mackey */*key*/); \ |
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149 | \ |
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150 | /* --- @pre_machash@ --- * \ |
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151 | * \ |
152 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
153 | * @const void *buf@ = pointer to buffer \ |
154 | * @size_t sz@ = size of the buffer \ |
155 | * \ |
156 | * Returns: --- \ |
157 | * \ |
158 | * Use: Hashes a buffer. \ |
159 | */ \ |
160 | \ |
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161 | extern void pre##_machash(pre##_macctx */*ctx*/, \ |
162 | const void */*buf*/, size_t /*sz*/); \ |
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163 | \ |
164 | /* --- @pre_macdone@ --- * \ |
165 | * \ |
166 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
167 | * @void *mac@ = pointer to buffer to receive MAC \ |
168 | * \ |
169 | * Returns: --- \ |
170 | * \ |
171 | * Use: Returns the result of a MAC computation. \ |
172 | */ \ |
173 | \ |
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174 | extern void pre##_macdone(pre##_macctx */*ctx*/, void */*mac*/); \ |
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175 | \ |
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176 | /* --- Generic MAC interface --- */ \ |
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177 | \ |
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178 | extern const gcmac pre##_hmac; |
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179 | |
180 | /*----- That's all, folks -------------------------------------------------*/ |
181 | |
182 | #ifdef __cplusplus |
183 | } |
184 | #endif |
185 | |
186 | #endif |