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