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