3 * $Id: hmac.h,v 1.5 2001/04/03 19:35:45 mdw Exp $
5 * Generic code for HMAC and NMAC
7 * (c) 1998 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.5 2001/04/03 19:35:45 mdw
34 * Support the SSL HMAC variant (untested).
36 * Revision 1.4 2000/10/15 19:09:20 mdw
37 * Support HMAC mode for hash functions which need to store more state than
38 * the hash output size.
40 * Revision 1.3 2000/06/17 11:23:57 mdw
41 * New key size interface.
43 * Revision 1.2 1999/12/10 23:17:39 mdw
44 * Split mode macros into interface and implementation.
46 * Revision 1.1 1999/09/03 08:41:12 mdw
51 /*----- Notes on the HMAC and NMAC constructions --------------------------*
53 * Designed by Mihir Bellare, Ran Canetti and Hugo Krawczyk, NMAC is a method
54 * for constructing keyed message authentication algorithms from unkeyed hash
55 * functions. It has been proven to provide useful security given reasonable
56 * assumptions about the underlying hash function. HMAC is an alternative
57 * formulation which doesn't require low-level access to the hash function's
58 * implementation. NMAC was designed to allow MD5 has a suitable underlying
59 * hash function, even though doubts were already being raised about its
60 * collision resistance.
63 #ifndef CATACOMB_HMAC_H
64 #define CATACOMB_HMAC_H
70 /*----- Header files ------------------------------------------------------*/
74 #include <mLib/bits.h>
76 #ifndef CATACOMB_GMAC_H
80 /*----- Macros ------------------------------------------------------------*/
82 /* --- @HMAC_DECL@ --- *
84 * Arguments: @PRE@, @pre@ = prefixes for the underlying hash function
86 * Use: Creates declarations for the HMAC and NMAC functions.
89 #define HMAC_DECL(PRE, pre) \
91 /* --- An HMAC or NMAC key --- */ \
93 typedef struct pre##_mackey { \
94 octet ochain[PRE##_STATESZ]; /* Chaining for outer hash */ \
95 unsigned ocount; /* Byte count for outer hash */ \
96 octet ichain[PRE##_STATESZ]; /* Chaining for inner hash */ \
97 unsigned icount; /* Byte count for inner hash */ \
100 /* --- An HMAC or NMAC hashing context --- */ \
102 typedef struct pre##_macctx { \
103 pre##_ctx ctx; /* Context for main hashing */ \
104 octet chain[PRE##_STATESZ]; /* Chaining for outer hash */ \
105 unsigned count; /* Byte count for outer hash */ \
108 /* --- Other useful constants --- */ \
110 extern const octet pre##_mackeysz[]; \
112 /* --- @pre_nmacinit@ --- * \
114 * Arguments: @pre_macctx *key@ = pointer to a MAC key object \
115 * @const void *ok@ = pointer to outer hash init vector \
116 * @const void *ik@ = pointer to inner hash init vector \
120 * Use: Initializes a MAC key for doing NMAC hashing. \
123 extern void pre##_nmacinit(pre##_mackey */*key*/, \
124 const void */*ok*/, const void */*ik*/); \
126 /* --- @pre_hmacinit@ --- * \
128 * Arguments: @pre_mackey *key@ = pointer to MAC key object \
129 * @const void *k@ = pointer to key to use \
130 * @size_t sz@ = size of key data \
134 * Use: Initializes a MAC key for doing HMAC hashing. Keys \
135 * longer than the hash function's output size aren't very \
136 * useful, but are accepted. Keys longer than the hash's \
137 * block size are also accepted; they are hashed before \
138 * use, as specified in RFC2104. \
141 extern void pre##_hmacinit(pre##_mackey */*key*/, \
142 const void */*k*/, size_t /*sz*/); \
144 /* --- @pre_sslmacinit@ --- * \
146 * Arguments: @pre_mackey *key@ = pointer to MAC key object \
147 * @const void *k@ = pointer to key to use \
148 * @size_t sz@ = size of key data \
152 * Use: Initializes a MAC key for doing hasing using the SSL3 \
156 extern void pre##_sslmacinit(pre##_mackey */*key*/, \
157 const void */*k*/, size_t /*sz*/); \
159 /* --- @pre_macinit@ --- * \
161 * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \
162 * @const pre_mackey *key@ = pointer to MAC key block \
166 * Use: Instantiates a MAC context from a key block. \
169 extern void pre##_macinit(pre##_macctx */*ctx*/, \
170 const pre##_mackey */*key*/); \
172 /* --- @pre_machash@ --- * \
174 * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \
175 * @const void *buf@ = pointer to buffer \
176 * @size_t sz@ = size of the buffer \
180 * Use: Hashes a buffer. \
183 extern void pre##_machash(pre##_macctx */*ctx*/, \
184 const void */*buf*/, size_t /*sz*/); \
186 /* --- @pre_macdone@ --- * \
188 * Arguments: @pre_macctx *ctx@ = pointer to MAC context block \
189 * @void *mac@ = pointer to buffer to receive MAC \
193 * Use: Returns the result of a MAC computation. \
196 extern void pre##_macdone(pre##_macctx */*ctx*/, void */*mac*/); \
198 /* --- Generic MAC interface --- */ \
200 extern const gcmac pre##_hmac;
202 /*----- That's all, folks -------------------------------------------------*/