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1 | /* -*-c-*- |
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2 | * |
3 | * Generic code for HMAC and NMAC |
4 | * |
5 | * (c) 1998 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Notes on the HMAC and NMAC constructions --------------------------* |
29 | * |
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30 | * Designed by Mihir Bellare, Ran Canetti and Hugo Krawczyk, NMAC is a method |
31 | * for constructing keyed message authentication algorithms from unkeyed hash |
32 | * functions. It has been proven to provide useful security given reasonable |
33 | * assumptions about the underlying hash function. HMAC is an alternative |
34 | * formulation which doesn't require low-level access to the hash function's |
35 | * implementation. NMAC was designed to allow MD5 has a suitable underlying |
36 | * hash function, even though doubts were already being raised about its |
37 | * collision resistance. |
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38 | */ |
39 | |
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40 | #ifndef CATACOMB_HMAC_H |
41 | #define CATACOMB_HMAC_H |
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42 | |
43 | #ifdef __cplusplus |
44 | extern "C" { |
45 | #endif |
46 | |
47 | /*----- Header files ------------------------------------------------------*/ |
48 | |
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49 | #include <stddef.h> |
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50 | |
51 | #include <mLib/bits.h> |
52 | |
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53 | #ifndef CATACOMB_GMAC_H |
54 | # include "gmac.h" |
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55 | #endif |
56 | |
57 | /*----- Macros ------------------------------------------------------------*/ |
58 | |
59 | /* --- @HMAC_DECL@ --- * |
60 | * |
61 | * Arguments: @PRE@, @pre@ = prefixes for the underlying hash function |
62 | * |
63 | * Use: Creates declarations for the HMAC and NMAC functions. |
64 | */ |
65 | |
66 | #define HMAC_DECL(PRE, pre) \ |
67 | \ |
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68 | /* --- An HMAC or NMAC key --- */ \ |
69 | \ |
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70 | typedef struct pre##_mackey { \ |
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71 | octet ochain[PRE##_STATESZ]; /* Chaining for outer hash */ \ |
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72 | unsigned ocount; /* Byte count for outer hash */ \ |
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73 | octet ichain[PRE##_STATESZ]; /* Chaining for inner hash */ \ |
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74 | unsigned icount; /* Byte count for inner hash */ \ |
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75 | } pre##_mackey; \ |
76 | \ |
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77 | /* --- An HMAC or NMAC hashing context --- */ \ |
78 | \ |
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79 | typedef struct pre##_macctx { \ |
80 | pre##_ctx ctx; /* Context for main hashing */ \ |
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81 | octet chain[PRE##_STATESZ]; /* Chaining for outer hash */ \ |
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82 | unsigned count; /* Byte count for outer hash */ \ |
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83 | } pre##_macctx; \ |
84 | \ |
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85 | /* --- Other useful constants --- */ \ |
86 | \ |
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87 | extern const octet pre##_hmackeysz[]; \ |
88 | extern const octet pre##_nmackeysz[]; \ |
89 | extern const octet pre##_sslmackeysz[]; \ |
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90 | \ |
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91 | /* --- @pre_nmacinit@ --- * \ |
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92 | * \ |
93 | * Arguments: @pre_macctx *key@ = pointer to a MAC key object \ |
94 | * @const void *ok@ = pointer to outer hash init vector \ |
95 | * @const void *ik@ = pointer to inner hash init vector \ |
96 | * \ |
97 | * Returns: --- \ |
98 | * \ |
99 | * Use: Initializes a MAC key for doing NMAC hashing. \ |
100 | */ \ |
101 | \ |
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102 | extern void pre##_nmacinit(pre##_mackey */*key*/, \ |
103 | const void */*ok*/, const void */*ik*/); \ |
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104 | \ |
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105 | /* --- @pre_hmacinit@ --- * \ |
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106 | * \ |
107 | * Arguments: @pre_mackey *key@ = pointer to MAC key object \ |
108 | * @const void *k@ = pointer to key to use \ |
109 | * @size_t sz@ = size of key data \ |
110 | * \ |
111 | * Returns: --- \ |
112 | * \ |
113 | * Use: Initializes a MAC key for doing HMAC hashing. Keys \ |
114 | * longer than the hash function's output size aren't very \ |
115 | * useful, but are accepted. Keys longer than the hash's \ |
116 | * block size are also accepted; they are hashed before \ |
117 | * use, as specified in RFC2104. \ |
118 | */ \ |
119 | \ |
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120 | extern void pre##_hmacinit(pre##_mackey */*key*/, \ |
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121 | const void */*k*/, size_t /*sz*/); \ |
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122 | \ |
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123 | /* --- @pre_sslmacinit@ --- * \ |
124 | * \ |
125 | * Arguments: @pre_mackey *key@ = pointer to MAC key object \ |
126 | * @const void *k@ = pointer to key to use \ |
127 | * @size_t sz@ = size of key data \ |
128 | * \ |
129 | * Returns: --- \ |
130 | * \ |
131 | * Use: Initializes a MAC key for doing hasing using the SSL3 \ |
132 | * variant of HMAC. \ |
133 | */ \ |
134 | \ |
135 | extern void pre##_sslmacinit(pre##_mackey */*key*/, \ |
136 | const void */*k*/, size_t /*sz*/); \ |
137 | \ |
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138 | /* --- @pre_macinit@ --- * \ |
139 | * \ |
140 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
141 | * @const pre_mackey *key@ = pointer to MAC key block \ |
142 | * \ |
143 | * Returns: --- \ |
144 | * \ |
145 | * Use: Instantiates a MAC context from a key block. \ |
146 | */ \ |
147 | \ |
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148 | extern void pre##_macinit(pre##_macctx */*ctx*/, \ |
149 | const pre##_mackey */*key*/); \ |
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150 | \ |
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151 | /* --- @pre_machash@ --- * \ |
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152 | * \ |
153 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
154 | * @const void *buf@ = pointer to buffer \ |
155 | * @size_t sz@ = size of the buffer \ |
156 | * \ |
157 | * Returns: --- \ |
158 | * \ |
159 | * Use: Hashes a buffer. \ |
160 | */ \ |
161 | \ |
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162 | extern void pre##_machash(pre##_macctx */*ctx*/, \ |
163 | const void */*buf*/, size_t /*sz*/); \ |
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164 | \ |
165 | /* --- @pre_macdone@ --- * \ |
166 | * \ |
167 | * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \ |
168 | * @void *mac@ = pointer to buffer to receive MAC \ |
169 | * \ |
170 | * Returns: --- \ |
171 | * \ |
172 | * Use: Returns the result of a MAC computation. \ |
173 | */ \ |
174 | \ |
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175 | extern void pre##_macdone(pre##_macctx */*ctx*/, void */*mac*/); \ |
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176 | \ |
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177 | /* --- Generic MAC interface --- */ \ |
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178 | \ |
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179 | extern const gcmac pre##_hmac; \ |
180 | extern const gcmac pre##_nmac; \ |
181 | extern const gcmac pre##_sslmac; |
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182 | |
183 | /*----- That's all, folks -------------------------------------------------*/ |
184 | |
185 | #ifdef __cplusplus |
186 | } |
187 | #endif |
188 | |
189 | #endif |