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1 | /* -*-c-*- |
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2 | * |
3 | * Implementation of the SHA-256 hash function |
4 | * |
5 | * (c) 2000 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 SHA-256 hash function --------------------------------* |
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29 | * |
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. |
34 | */ |
35 | |
36 | #ifndef CATACOMB_SHA256_H |
37 | #define CATACOMB_SHA256_H |
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38 | #define CATACOMB_SHA224_H |
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39 | |
40 | #ifdef __cplusplus |
41 | extern "C" { |
42 | #endif |
43 | |
44 | /*----- Header files ------------------------------------------------------*/ |
45 | |
46 | #include <mLib/bits.h> |
47 | |
48 | #ifndef CATACOMB_GHASH_H |
49 | # include "ghash.h" |
50 | #endif |
51 | |
52 | /*----- Magic numbers -----------------------------------------------------*/ |
53 | |
54 | #define SHA256_BUFSZ 64 |
55 | #define SHA256_HASHSZ 32 |
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56 | #define SHA256_STATESZ 32 |
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57 | |
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58 | #define SHA224_BUFSZ 64 |
59 | #define SHA224_HASHSZ 28 |
60 | #define SHA224_STATESZ 32 |
61 | |
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62 | /*----- Data structures ---------------------------------------------------*/ |
63 | |
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 */ |
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69 | } sha256_ctx, sha224_ctx; |
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70 | |
71 | /*----- Functions provided ------------------------------------------------*/ |
72 | |
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73 | /* --- @sha256_compress@, @sha224_compress@ --- * |
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74 | * |
75 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
76 | * @const void *sbuf@ = pointer to buffer of appropriate size |
77 | * |
78 | * Returns: --- |
79 | * |
80 | * Use: SHA-256 compression function. |
81 | */ |
82 | |
83 | extern void sha256_compress(sha256_ctx */*ctx*/, const void */*sbuf*/); |
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84 | #define sha224_compress sha256_compress |
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85 | |
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86 | /* --- @sha256_init@, @sha224_init@ --- * |
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87 | * |
88 | * Arguments: @sha256_ctx *ctx@ = pointer to context block to initialize |
89 | * |
90 | * Returns: --- |
91 | * |
92 | * Use: Initializes a context block ready for hashing. |
93 | */ |
94 | |
95 | extern void sha256_init(sha256_ctx */*ctx*/); |
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96 | extern void sha224_init(sha256_ctx */*ctx*/); |
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97 | |
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98 | /* --- @sha256_set@, @sha224_set@ --- * |
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99 | * |
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 |
103 | * |
104 | * Returns: --- |
105 | * |
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. |
109 | */ |
110 | |
111 | extern void sha256_set(sha256_ctx */*ctx*/, const void */*buf*/, |
112 | unsigned long /*count*/); |
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113 | #define sha224_set sha256_set |
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114 | |
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115 | /* --- @sha256_hash@, @sha224_hash@ --- * |
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116 | * |
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 |
120 | * |
121 | * Returns: --- |
122 | * |
123 | * Use: Hashes a buffer of data. The buffer may be of any size and |
124 | * alignment. |
125 | */ |
126 | |
127 | extern void sha256_hash(sha256_ctx */*ctx*/, |
128 | const void */*buf*/, size_t /*sz*/); |
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129 | #define sha224_hash sha256_hash |
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130 | |
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131 | /* --- @sha256_done@, @sha224_done@ --- * |
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132 | * |
133 | * Arguments: @sha256_ctx *ctx@ = pointer to context block |
134 | * @void *hash@ = pointer to output buffer |
135 | * |
136 | * Returns: --- |
137 | * |
138 | * Use: Returns the hash of the data read so far. |
139 | */ |
140 | |
141 | extern void sha256_done(sha256_ctx */*ctx*/, void */*hash*/); |
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142 | extern void sha224_done(sha256_ctx */*ctx*/, void */*hash*/); |
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143 | |
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144 | /* --- @sha256_state@, @sha224_state@ --- * |
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145 | * |
146 | * Arguments: @sha256_ctx *ctx@ = pointer to context |
147 | * @void *state@ = pointer to buffer for current state |
148 | * |
149 | * Returns: Number of bytes written to the hash function so far. |
150 | * |
151 | * Use: Returns the current state of the hash function such that |
152 | * it can be passed to @sha256_set@. |
153 | */ |
154 | |
155 | extern unsigned long sha256_state(sha256_ctx */*ctx*/, void */*state*/); |
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156 | #define sha224_state sha256_state |
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157 | |
158 | /*----- Generic hash interface --------------------------------------------*/ |
159 | |
160 | extern const gchash sha256; |
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161 | extern const gchash sha224; |
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162 | |
163 | /*----- That's all, folks -------------------------------------------------*/ |
164 | |
165 | #ifdef __cplusplus |
166 | } |
167 | #endif |
168 | |
169 | #endif |