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1 | /* -*-c-*- |
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2 | * |
3 | * Ciphertext block chaining for block ciphers |
4 | * |
5 | * (c) 1999 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 | #ifndef CATACOMB_CBC_H |
29 | #define CATACOMB_CBC_H |
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30 | |
31 | #ifdef __cplusplus |
32 | extern "C" { |
33 | #endif |
34 | |
35 | /*----- Header files ------------------------------------------------------*/ |
36 | |
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37 | #include <stddef.h> |
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38 | |
39 | #include <mLib/bits.h> |
40 | |
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41 | #ifndef CATACOMB_GCIPHER_H |
42 | # include "gcipher.h" |
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43 | #endif |
44 | |
45 | /*----- Macros ------------------------------------------------------------*/ |
46 | |
47 | /* --- @CBC_DECL@ --- * |
48 | * |
49 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
50 | * |
51 | * Use: Creates declarations for CBC stealing mode. |
52 | */ |
53 | |
54 | #define CBC_DECL(PRE, pre) \ |
55 | \ |
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56 | /* --- Cipher block chaining context --- */ \ |
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57 | \ |
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58 | typedef struct pre##_cbcctx { \ |
59 | pre##_ctx ctx; /* Underlying cipher context */ \ |
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60 | uint32 a[PRE##_BLKSZ/4]; /* Previous ciphertext or IV */ \ |
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61 | } pre##_cbcctx; \ |
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62 | \ |
63 | /* --- @pre_cbcgetiv@ --- * \ |
64 | * \ |
65 | * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \ |
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66 | * @void *iv@ = pointer to output data block \ |
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67 | * \ |
68 | * Returns: --- \ |
69 | * \ |
70 | * Use: Reads the currently set IV. Reading and setting an IV \ |
71 | * is transparent to the CBC encryption or decryption \ |
72 | * process. \ |
73 | */ \ |
74 | \ |
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75 | extern void pre##_cbcgetiv(const pre##_cbcctx */*ctx*/, \ |
76 | void */*iv*/); \ |
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77 | \ |
78 | /* --- @pre_cbcsetiv@ --- * \ |
79 | * \ |
80 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
81 | * @cnost void *iv@ = pointer to IV to set \ |
82 | * \ |
83 | * Returns: --- \ |
84 | * \ |
85 | * Use: Sets the IV to use for subsequent encryption. \ |
86 | */ \ |
87 | \ |
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88 | extern void pre##_cbcsetiv(pre##_cbcctx */*ctx*/, \ |
89 | const void */*iv*/); \ |
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90 | \ |
91 | /* --- @pre_cbcsetkey@ --- * \ |
92 | * \ |
93 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
94 | * @const pre_ctx *k@ = pointer to cipher context \ |
95 | * \ |
96 | * Returns: --- \ |
97 | * \ |
98 | * Use: Sets the CBC context to use a different cipher key. \ |
99 | */ \ |
100 | \ |
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101 | extern void pre##_cbcsetkey(pre##_cbcctx */*ctx*/, \ |
102 | const pre##_ctx */*k*/); \ |
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103 | \ |
104 | /* --- @pre_cbcinit@ --- * \ |
105 | * \ |
106 | * Arguments: @pre_cbcctx *ctx@ = pointer to cipher context \ |
107 | * @const void *key@ = pointer to the key buffer \ |
108 | * @size_t sz@ = size of the key \ |
109 | * @const void *iv@ = pointer to initialization vector \ |
110 | * \ |
111 | * Returns: --- \ |
112 | * \ |
113 | * Use: Initializes a CBC context ready for use. The @iv@ \ |
114 | * argument may be passed as a null pointer to set a zero \ |
115 | * IV. Apart from that, this call is equivalent to calls \ |
116 | * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \ |
117 | */ \ |
118 | \ |
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119 | extern void pre##_cbcinit(pre##_cbcctx */*ctx*/, \ |
120 | const void */*key*/, size_t /*sz*/, \ |
121 | const void */*iv*/); \ |
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122 | \ |
123 | /* --- @pre_cbcencrypt@ --- * \ |
124 | * \ |
125 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
126 | * @const void *src@ = pointer to source data \ |
127 | * @void *dest@ = pointer to destination data \ |
128 | * @size_t sz@ = size of block to be encrypted \ |
129 | * \ |
130 | * Returns: --- \ |
131 | * \ |
132 | * Use: Encrypts a block with a block cipher in CBC mode, with \ |
133 | * ciphertext stealing and other clever tricks. \ |
134 | * Essentially, data can be encrypted in arbitrary sized \ |
135 | * chunks, although decryption must use the same chunks. \ |
136 | */ \ |
137 | \ |
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138 | extern void pre##_cbcencrypt(pre##_cbcctx */*ctx*/, \ |
139 | const void */*src*/, void */*dest*/, \ |
140 | size_t /*sz*/); \ |
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141 | \ |
142 | /* --- @pre_cbcdecrypt@ --- * \ |
143 | * \ |
144 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ |
145 | * @const void *src@ = pointer to source data \ |
146 | * @void *dest@ = pointer to destination data \ |
147 | * @size_t sz@ = size of block to be encrypted \ |
148 | * \ |
149 | * Returns: --- \ |
150 | * \ |
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151 | * Use: Decrypts a block with a block cipher in CBC mode, with \ |
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152 | * ciphertext stealing and other clever tricks. \ |
153 | * Essentially, data can be encrypted in arbitrary sized \ |
154 | * chunks, although decryption must use the same chunks. \ |
155 | */ \ |
156 | \ |
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157 | extern void pre##_cbcdecrypt(pre##_cbcctx */*ctx*/, \ |
158 | const void */*src*/, void */*dest*/, \ |
159 | size_t /*sz*/); \ |
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160 | \ |
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161 | /* --- Generic cipher interface --- */ \ |
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162 | \ |
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163 | extern const gccipher pre##_cbc; |
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164 | |
165 | /*----- That's all, folks -------------------------------------------------*/ |
166 | |
167 | #ifdef __cplusplus |
168 | } |
169 | #endif |
170 | |
171 | #endif |