3 * $Id: sha256.h,v 1.2 2000/10/15 19:09:20 mdw Exp $
5 * Implementation of the SHA-256 hash function
7 * (c) 2000 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 1.2 2000/10/15 19:09:20 mdw
34 * Support HMAC mode for hash functions which need to store more state than
35 * the hash output size.
37 * Revision 1.1 2000/10/15 17:48:15 mdw
38 * New SHA variants with longer outputs.
42 /*----- Notes on the SHA-256 hash function ----------------------------------*
44 * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
45 * Digital Signature Algorithm. This is an evolution with a larger output
46 * size, intended to provide security commensurate with 128-bit AES. At the
47 * time of writing, SHA-256 is very new, and can't be trusted too far.
50 #ifndef CATACOMB_SHA256_H
51 #define CATACOMB_SHA256_H
57 /*----- Header files ------------------------------------------------------*/
59 #include <mLib/bits.h>
61 #ifndef CATACOMB_GHASH_H
65 /*----- Magic numbers -----------------------------------------------------*/
67 #define SHA256_BUFSZ 64
68 #define SHA256_HASHSZ 32
69 #define SHA256_STATESZ 32
71 /*----- Data structures ---------------------------------------------------*/
73 typedef struct sha256_ctx
{
74 uint32 a
, b
, c
, d
, e
, f
, g
, h
; /* Chaining variables */
75 uint32 nl
, nh
; /* Byte count so far */
76 unsigned off
; /* Offset into buffer */
77 octet buf
[SHA256_BUFSZ
]; /* Accumulation buffer */
80 /*----- Functions provided ------------------------------------------------*/
82 /* --- @sha256_compress@ --- *
84 * Arguments: @sha256_ctx *ctx@ = pointer to context block
85 * @const void *sbuf@ = pointer to buffer of appropriate size
89 * Use: SHA-256 compression function.
92 extern void sha256_compress(sha256_ctx */
*ctx*/
, const void */
*sbuf*/
);
94 /* --- @sha256_init@ --- *
96 * Arguments: @sha256_ctx *ctx@ = pointer to context block to initialize
100 * Use: Initializes a context block ready for hashing.
103 extern void sha256_init(sha256_ctx */
*ctx*/
);
105 /* --- @sha256_set@ --- *
107 * Arguments: @sha256_ctx *ctx@ = pointer to context block
108 * @const void *buf@ = pointer to state buffer
109 * @unsigned long count@ = current count of bytes processed
113 * Use: Initializes a context block from a given state. This is
114 * useful in cases where the initial hash state is meant to be
115 * secret, e.g., for NMAC and HMAC support.
118 extern void sha256_set(sha256_ctx */
*ctx*/
, const void */
*buf*/
,
119 unsigned long /*count*/);
121 /* --- @sha256_hash@ --- *
123 * Arguments: @sha256_ctx *ctx@ = pointer to context block
124 * @const void *buf@ = buffer of data to hash
125 * @size_t sz@ = size of buffer to hash
129 * Use: Hashes a buffer of data. The buffer may be of any size and
133 extern void sha256_hash(sha256_ctx */
*ctx*/
,
134 const void */
*buf*/
, size_t /*sz*/);
136 /* --- @sha256_done@ --- *
138 * Arguments: @sha256_ctx *ctx@ = pointer to context block
139 * @void *hash@ = pointer to output buffer
143 * Use: Returns the hash of the data read so far.
146 extern void sha256_done(sha256_ctx */
*ctx*/
, void */
*hash*/
);
148 /* --- @sha256_state@ --- *
150 * Arguments: @sha256_ctx *ctx@ = pointer to context
151 * @void *state@ = pointer to buffer for current state
153 * Returns: Number of bytes written to the hash function so far.
155 * Use: Returns the current state of the hash function such that
156 * it can be passed to @sha256_set@.
159 extern unsigned long sha256_state(sha256_ctx */
*ctx*/
, void */
*state*/
);
161 /*----- Generic hash interface --------------------------------------------*/
163 extern const gchash sha256
;
165 /*----- That's all, folks -------------------------------------------------*/