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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: cfb.h,v 1.4 2001/06/17 00:10:51 mdw Exp $ |
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4 | * |
5 | * Ciphertext feedback for block ciphers |
6 | * |
7 | * (c) 1999 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 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: cfb.h,v $ |
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33 | * Revision 1.4 2001/06/17 00:10:51 mdw |
34 | * Typesetting fixes |
35 | * |
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36 | * Revision 1.3 2000/06/17 10:50:55 mdw |
37 | * Change buffer offset to be unsigned. |
38 | * |
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39 | * Revision 1.2 1999/12/10 23:16:39 mdw |
40 | * Split mode macros into interface and implementation. |
41 | * |
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42 | * Revision 1.1 1999/09/03 08:41:11 mdw |
43 | * Initial import. |
44 | * |
45 | */ |
46 | |
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47 | #ifndef CATACOMB_CFB_H |
48 | #define CATACOMB_CFB_H |
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49 | |
50 | #ifdef __cplusplus |
51 | extern "C" { |
52 | #endif |
53 | |
54 | /*----- Header files ------------------------------------------------------*/ |
55 | |
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56 | #include <stddef.h> |
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57 | |
58 | #include <mLib/bits.h> |
59 | |
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60 | #ifndef CATACOMB_GCIPHER_H |
61 | # include "gcipher.h" |
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62 | #endif |
63 | |
64 | /*----- Data structures ---------------------------------------------------*/ |
65 | |
66 | /* --- @CFB_DECL@ --- * |
67 | * |
68 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
69 | * |
70 | * Use: Creates declarations for CFB mode. |
71 | */ |
72 | |
73 | #define CFB_DECL(PRE, pre) \ |
74 | \ |
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75 | /* --- Ciphertext feedback context --- */ \ |
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76 | \ |
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77 | typedef struct pre##_cfbctx { \ |
78 | pre##_ctx ctx; /* Underlying cipher context */ \ |
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79 | unsigned off; /* Offset into @iv@ buffer */ \ |
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80 | octet iv[PRE##_BLKSZ]; /* Previous ciphertext or IV */ \ |
81 | } pre##_cfbctx; \ |
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82 | \ |
83 | /* --- @pre_cfbgetiv@ --- * \ |
84 | * \ |
85 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ |
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86 | * @void *iv@ = pointer to output data block \ |
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87 | * \ |
88 | * Returns: --- \ |
89 | * \ |
90 | * Use: Reads the currently set IV. Reading and setting an IV \ |
91 | * is not transparent to the cipher. It will add a `step' \ |
92 | * which must be matched by a similar operation during \ |
93 | * decryption. \ |
94 | */ \ |
95 | \ |
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96 | extern void pre##_cfbgetiv(const pre##_cfbctx */*ctx*/, \ |
97 | void */*iv*/); \ |
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98 | \ |
99 | /* --- @pre_cfbsetiv@ --- * \ |
100 | * \ |
101 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
102 | * @cnost void *iv@ = pointer to IV to set \ |
103 | * \ |
104 | * Returns: --- \ |
105 | * \ |
106 | * Use: Sets the IV to use for subsequent encryption. \ |
107 | */ \ |
108 | \ |
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109 | extern void pre##_cfbsetiv(pre##_cfbctx */*ctx*/, \ |
110 | const void */*iv*/); \ |
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111 | \ |
112 | /* --- @pre_cfbbdry@ --- * \ |
113 | * \ |
114 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
115 | * \ |
116 | * Returns: --- \ |
117 | * \ |
118 | * Use: Inserts a boundary during encryption. Successful \ |
119 | * decryption must place a similar boundary. \ |
120 | */ \ |
121 | \ |
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122 | extern void pre##_cfbbdry(pre##_cfbctx */*ctx*/); \ |
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123 | \ |
124 | /* --- @pre_cfbsetkey@ --- * \ |
125 | * \ |
126 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
127 | * @const pre_ctx *k@ = pointer to cipher context \ |
128 | * \ |
129 | * Returns: --- \ |
130 | * \ |
131 | * Use: Sets the CFB context to use a different cipher key. \ |
132 | */ \ |
133 | \ |
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134 | extern void pre##_cfbsetkey(pre##_cfbctx */*ctx*/, \ |
135 | const pre##_ctx */*k*/); \ |
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136 | \ |
137 | /* --- @pre_cfbinit@ --- * \ |
138 | * \ |
139 | * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \ |
140 | * @const void *key@ = pointer to the key buffer \ |
141 | * @size_t sz@ = size of the key \ |
142 | * @const void *iv@ = pointer to initialization vector \ |
143 | * \ |
144 | * Returns: --- \ |
145 | * \ |
146 | * Use: Initializes a CFB context ready for use. You should \ |
147 | * ensure that the IV chosen is unique: reusing an IV will \ |
148 | * compromise the security of at least the first block \ |
149 | * encrypted. This is equivalent to calls to @pre_init@, \ |
150 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ |
151 | */ \ |
152 | \ |
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153 | extern void pre##_cfbinit(pre##_cfbctx */*ctx*/, \ |
154 | const void */*key*/, size_t /*sz*/, \ |
155 | const void */*iv*/); \ |
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156 | \ |
157 | /* --- @pre_cfbencrypt@ --- * \ |
158 | * \ |
159 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
160 | * @const void *src@ = pointer to source data \ |
161 | * @void *dest@ = pointer to destination data \ |
162 | * @size_t sz@ = size of block to be encrypted \ |
163 | * \ |
164 | * Returns: --- \ |
165 | * \ |
166 | * Use: Encrypts a block with a block cipher in CFB mode. The \ |
167 | * input block may be arbitrary in size. CFB mode is not \ |
168 | * sensitive to block boundaries. \ |
169 | */ \ |
170 | \ |
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171 | extern void pre##_cfbencrypt(pre##_cfbctx */*ctx*/, \ |
172 | const void */*src*/, void */*dest*/, \ |
173 | size_t /*sz*/); \ |
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174 | \ |
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175 | /* --- @pre_cfbencrypt@ --- * \ |
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176 | * \ |
177 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ |
178 | * @const void *src@ = pointer to source data \ |
179 | * @void *dest@ = pointer to destination data \ |
180 | * @size_t sz@ = size of block to be encrypted \ |
181 | * \ |
182 | * Returns: --- \ |
183 | * \ |
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184 | * Use: Decrypts a block with a block cipher in CFB mode. The \ |
185 | * input block may be arbitrary in size. CFB mode is not \ |
186 | * sensitive to block boundaries. \ |
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187 | */ \ |
188 | \ |
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189 | extern void pre##_cfbdecrypt(pre##_cfbctx */*ctx*/, \ |
190 | const void */*src*/, void */*dest*/, \ |
191 | size_t /*sz*/); \ |
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192 | \ |
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193 | /* --- Generic cipher interface --- */ \ |
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194 | \ |
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195 | extern const gccipher pre##_cfb; |
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196 | |
197 | /*----- That's all, folks -------------------------------------------------*/ |
198 | |
199 | #ifdef __cplusplus |
200 | } |
201 | #endif |
202 | |
203 | #endif |