3 * Implementation of the SHA-256 hash function
5 * (c) 2000 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
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.
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.
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,
28 /*----- Notes on the SHA-256 hash function --------------------------------*
30 * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the
31 * Digital Signature Algorithm. This is an evolution with a larger output
32 * size, intended to provide security commensurate with 128-bit AES. At the
33 * time of writing, SHA-256 is very new, and can't be trusted too far.
36 #ifndef CATACOMB_SHA256_H
37 #define CATACOMB_SHA256_H
38 #define CATACOMB_SHA224_H
44 /*----- Header files ------------------------------------------------------*/
46 #include <mLib/bits.h>
48 #ifndef CATACOMB_GHASH_H
52 /*----- Magic numbers -----------------------------------------------------*/
54 #define SHA256_BUFSZ 64
55 #define SHA256_HASHSZ 32
56 #define SHA256_STATESZ 32
58 #define SHA224_BUFSZ 64
59 #define SHA224_HASHSZ 28
60 #define SHA224_STATESZ 32
62 /*----- Data structures ---------------------------------------------------*/
64 typedef struct sha256_ctx {
65 uint32 a, b, c, d, e, f, g, h; /* Chaining variables */
66 uint32 nl, nh; /* Byte count so far */
67 unsigned off; /* Offset into buffer */
68 octet buf[SHA256_BUFSZ]; /* Accumulation buffer */
69 } sha256_ctx, sha224_ctx;
71 /*----- Functions provided ------------------------------------------------*/
73 /* --- @sha256_compress@, @sha224_compress@ --- *
75 * Arguments: @sha256_ctx *ctx@ = pointer to context block
76 * @const void *sbuf@ = pointer to buffer of appropriate size
80 * Use: SHA-256 compression function.
83 extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/);
84 #define sha224_compress sha256_compress
86 /* --- @sha256_init@, @sha224_init@ --- *
88 * Arguments: @sha256_ctx *ctx@ = pointer to context block to initialize
92 * Use: Initializes a context block ready for hashing.
95 extern void sha256_init(sha256_ctx */*ctx*/);
96 extern void sha224_init(sha256_ctx */*ctx*/);
98 /* --- @sha256_set@, @sha224_set@ --- *
100 * Arguments: @sha256_ctx *ctx@ = pointer to context block
101 * @const void *buf@ = pointer to state buffer
102 * @unsigned long count@ = current count of bytes processed
106 * Use: Initializes a context block from a given state. This is
107 * useful in cases where the initial hash state is meant to be
108 * secret, e.g., for NMAC and HMAC support.
111 extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/,
112 unsigned long /*count*/);
113 #define sha224_set sha256_set
115 /* --- @sha256_hash@, @sha224_hash@ --- *
117 * Arguments: @sha256_ctx *ctx@ = pointer to context block
118 * @const void *buf@ = buffer of data to hash
119 * @size_t sz@ = size of buffer to hash
123 * Use: Hashes a buffer of data. The buffer may be of any size and
127 extern void sha256_hash(sha256_ctx */*ctx*/,
128 const void */*buf*/, size_t /*sz*/);
129 #define sha224_hash sha256_hash
131 /* --- @sha256_done@, @sha224_done@ --- *
133 * Arguments: @sha256_ctx *ctx@ = pointer to context block
134 * @void *hash@ = pointer to output buffer
138 * Use: Returns the hash of the data read so far.
141 extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/);
142 extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/);
144 /* --- @sha256_state@, @sha224_state@ --- *
146 * Arguments: @sha256_ctx *ctx@ = pointer to context
147 * @void *state@ = pointer to buffer for current state
149 * Returns: Number of bytes written to the hash function so far.
151 * Use: Returns the current state of the hash function such that
152 * it can be passed to @sha256_set@.
155 extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/);
156 #define sha224_state sha256_state
158 /*----- Generic hash interface --------------------------------------------*/
160 extern const gchash sha256;
161 extern const gchash sha224;
163 /*----- That's all, folks -------------------------------------------------*/