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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * Implementation of the SHA-256 hash function |
6 | * |
7 | * (c) 2000 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 | |
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30 | /*----- Notes on the SHA-256 hash function --------------------------------* |
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31 | * |
32 | * SHA-1 (Secure Hash Algorithm) was designed by the NSA, for use with the |
33 | * Digital Signature Algorithm. This is an evolution with a larger output |
34 | * size, intended to provide security commensurate with 128-bit AES. At the |
35 | * time of writing, SHA-256 is very new, and can't be trusted too far. |
36 | */ |
37 | |
38 | #ifndef CATACOMB_SHA256_H |
39 | #define CATACOMB_SHA256_H |
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40 | #define CATACOMB_SHA224_H |
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41 | |
42 | #ifdef __cplusplus |
43 | extern "C" { |
44 | #endif |
45 | |
46 | /*----- Header files ------------------------------------------------------*/ |
47 | |
48 | #include <mLib/bits.h> |
49 | |
50 | #ifndef CATACOMB_GHASH_H |
51 | # include "ghash.h" |
52 | #endif |
53 | |
54 | /*----- Magic numbers -----------------------------------------------------*/ |
55 | |
56 | #define SHA256_BUFSZ 64 |
57 | #define SHA256_HASHSZ 32 |
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58 | #define SHA256_STATESZ 32 |
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59 | |
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60 | #define SHA224_BUFSZ 64 |
61 | #define SHA224_HASHSZ 28 |
62 | #define SHA224_STATESZ 32 |
63 | |
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64 | /*----- Data structures ---------------------------------------------------*/ |
65 | |
66 | typedef struct sha256_ctx { |
67 | uint32 a, b, c, d, e, f, g, h; /* Chaining variables */ |
68 | uint32 nl, nh; /* Byte count so far */ |
69 | unsigned off; /* Offset into buffer */ |
70 | octet buf[SHA256_BUFSZ]; /* Accumulation buffer */ |
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71 | } sha256_ctx, sha224_ctx; |
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72 | |
73 | /*----- Functions provided ------------------------------------------------*/ |
74 | |
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75 | /* --- @sha256_compress@, @sha224_compress@ --- * |
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76 | * |
77 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
78 | * @const void *sbuf@ = pointer to buffer of appropriate size |
79 | * |
80 | * Returns: --- |
81 | * |
82 | * Use: SHA-256 compression function. |
83 | */ |
84 | |
85 | extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/); |
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86 | #define sha224_compress sha256_compress |
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87 | |
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88 | /* --- @sha256_init@, @sha224_init@ --- * |
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89 | * |
90 | * Arguments: @sha256_ctx *ctx@ = pointer to context block to initialize |
91 | * |
92 | * Returns: --- |
93 | * |
94 | * Use: Initializes a context block ready for hashing. |
95 | */ |
96 | |
97 | extern void sha256_init(sha256_ctx */*ctx*/); |
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98 | extern void sha224_init(sha256_ctx */*ctx*/); |
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99 | |
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100 | /* --- @sha256_set@, @sha224_set@ --- * |
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101 | * |
102 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
103 | * @const void *buf@ = pointer to state buffer |
104 | * @unsigned long count@ = current count of bytes processed |
105 | * |
106 | * Returns: --- |
107 | * |
108 | * Use: Initializes a context block from a given state. This is |
109 | * useful in cases where the initial hash state is meant to be |
110 | * secret, e.g., for NMAC and HMAC support. |
111 | */ |
112 | |
113 | extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/, |
114 | unsigned long /*count*/); |
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115 | #define sha224_set sha256_set |
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116 | |
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117 | /* --- @sha256_hash@, @sha224_hash@ --- * |
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118 | * |
119 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
120 | * @const void *buf@ = buffer of data to hash |
121 | * @size_t sz@ = size of buffer to hash |
122 | * |
123 | * Returns: --- |
124 | * |
125 | * Use: Hashes a buffer of data. The buffer may be of any size and |
126 | * alignment. |
127 | */ |
128 | |
129 | extern void sha256_hash(sha256_ctx */*ctx*/, |
130 | const void */*buf*/, size_t /*sz*/); |
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131 | #define sha224_hash sha256_hash |
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132 | |
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133 | /* --- @sha256_done@, @sha224_done@ --- * |
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134 | * |
135 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
136 | * @void *hash@ = pointer to output buffer |
137 | * |
138 | * Returns: --- |
139 | * |
140 | * Use: Returns the hash of the data read so far. |
141 | */ |
142 | |
143 | extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/); |
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144 | extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/); |
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145 | |
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146 | /* --- @sha256_state@, @sha224_state@ --- * |
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147 | * |
148 | * Arguments: @sha256_ctx *ctx@ = pointer to context |
149 | * @void *state@ = pointer to buffer for current state |
150 | * |
151 | * Returns: Number of bytes written to the hash function so far. |
152 | * |
153 | * Use: Returns the current state of the hash function such that |
154 | * it can be passed to @sha256_set@. |
155 | */ |
156 | |
157 | extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/); |
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158 | #define sha224_state sha256_state |
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159 | |
160 | /*----- Generic hash interface --------------------------------------------*/ |
161 | |
162 | extern const gchash sha256; |
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163 | extern const gchash sha224; |
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164 | |
165 | /*----- That's all, folks -------------------------------------------------*/ |
166 | |
167 | #ifdef __cplusplus |
168 | } |
169 | #endif |
170 | |
171 | #endif |