| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: ofb.h,v 1.4 2001/06/17 00:10:51 mdw Exp $ |
| 4 | * |
| 5 | * Output 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: ofb.h,v $ |
| 33 | * Revision 1.4 2001/06/17 00:10:51 mdw |
| 34 | * Typesetting fixes |
| 35 | * |
| 36 | * Revision 1.3 2000/06/17 11:48:24 mdw |
| 37 | * Change buffer offset to be unsigned. |
| 38 | * |
| 39 | * Revision 1.2 1999/12/10 23:16:40 mdw |
| 40 | * Split mode macros into interface and implementation. |
| 41 | * |
| 42 | * Revision 1.1 1999/09/03 08:41:12 mdw |
| 43 | * Initial import. |
| 44 | * |
| 45 | */ |
| 46 | |
| 47 | #ifndef CATACOMB_OFB_H |
| 48 | #define CATACOMB_OFB_H |
| 49 | |
| 50 | #ifdef __cplusplus |
| 51 | extern "C" { |
| 52 | #endif |
| 53 | |
| 54 | /*----- Header files ------------------------------------------------------*/ |
| 55 | |
| 56 | #include <stddef.h> |
| 57 | |
| 58 | #include <mLib/bits.h> |
| 59 | |
| 60 | #ifndef CATACOMB_GCIPHER_H |
| 61 | # include "gcipher.h" |
| 62 | #endif |
| 63 | |
| 64 | #ifndef CATACOMB_GRAND_H |
| 65 | # include "grand.h" |
| 66 | #endif |
| 67 | |
| 68 | /*----- Macros ------------------------------------------------------------*/ |
| 69 | |
| 70 | /* --- @OFB_DECL@ --- * |
| 71 | * |
| 72 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
| 73 | * |
| 74 | * Use: Makes declarations for output feedback mode. |
| 75 | */ |
| 76 | |
| 77 | #define OFB_DECL(PRE, pre) \ |
| 78 | \ |
| 79 | /* --- Output feedback context --- */ \ |
| 80 | \ |
| 81 | typedef struct pre##_ofbctx { \ |
| 82 | pre##_ctx ctx; /* Underlying cipher context */ \ |
| 83 | unsigned off; /* Current offset in buffer */ \ |
| 84 | octet iv[PRE##_BLKSZ]; /* Output buffer and IV */ \ |
| 85 | } pre##_ofbctx; \ |
| 86 | \ |
| 87 | /* --- @pre_ofbgetiv@ --- * \ |
| 88 | * \ |
| 89 | * Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \ |
| 90 | * @void *iv@ = pointer to output data block \ |
| 91 | * \ |
| 92 | * Returns: --- \ |
| 93 | * \ |
| 94 | * Use: Reads the currently set IV. Reading and setting an IV \ |
| 95 | * is not transparent to the cipher. It will add a `step' \ |
| 96 | * which must be matched by a similar operation during \ |
| 97 | * decryption. \ |
| 98 | */ \ |
| 99 | \ |
| 100 | extern void pre##_ofbgetiv(const pre##_ofbctx */*ctx*/, \ |
| 101 | void */*iv*/); \ |
| 102 | \ |
| 103 | /* --- @pre_ofbsetiv@ --- * \ |
| 104 | * \ |
| 105 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
| 106 | * @cnost void *iv@ = pointer to IV to set \ |
| 107 | * \ |
| 108 | * Returns: --- \ |
| 109 | * \ |
| 110 | * Use: Sets the IV to use for subsequent encryption. \ |
| 111 | */ \ |
| 112 | \ |
| 113 | extern void pre##_ofbsetiv(pre##_ofbctx */*ctx*/, \ |
| 114 | const void */*iv*/); \ |
| 115 | \ |
| 116 | /* --- @pre_ofbbdry@ --- * \ |
| 117 | * \ |
| 118 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
| 119 | * \ |
| 120 | * Returns: --- \ |
| 121 | * \ |
| 122 | * Use: Inserts a boundary during encryption. Successful \ |
| 123 | * decryption must place a similar boundary. \ |
| 124 | */ \ |
| 125 | \ |
| 126 | extern void pre##_ofbbdry(pre##_ofbctx */*ctx*/); \ |
| 127 | \ |
| 128 | /* --- @pre_ofbsetkey@ --- * \ |
| 129 | * \ |
| 130 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
| 131 | * @const pre_ctx *k@ = pointer to cipher context \ |
| 132 | * \ |
| 133 | * Returns: --- \ |
| 134 | * \ |
| 135 | * Use: Sets the OFB context to use a different cipher key. \ |
| 136 | */ \ |
| 137 | \ |
| 138 | extern void pre##_ofbsetkey(pre##_ofbctx */*ctx*/, \ |
| 139 | const pre##_ctx */*k*/); \ |
| 140 | \ |
| 141 | /* --- @pre_ofbinit@ --- * \ |
| 142 | * \ |
| 143 | * Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \ |
| 144 | * @const void *key@ = pointer to the key buffer \ |
| 145 | * @size_t sz@ = size of the key \ |
| 146 | * @const void *iv@ = pointer to initialization vector \ |
| 147 | * \ |
| 148 | * Returns: --- \ |
| 149 | * \ |
| 150 | * Use: Initializes a OFB context ready for use. You should \ |
| 151 | * ensure that the IV chosen is unique: reusing an IV will \ |
| 152 | * compromise the security of the entire plaintext. This \ |
| 153 | * is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \ |
| 154 | * and @pre_ofbsetiv@. \ |
| 155 | */ \ |
| 156 | \ |
| 157 | extern void pre##_ofbinit(pre##_ofbctx */*ctx*/, \ |
| 158 | const void */*key*/, size_t /*sz*/, \ |
| 159 | const void */*iv*/); \ |
| 160 | \ |
| 161 | /* --- @pre_ofbencrypt@ --- * \ |
| 162 | * \ |
| 163 | * Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \ |
| 164 | * @const void *src@ = pointer to source data \ |
| 165 | * @void *dest@ = pointer to destination data \ |
| 166 | * @size_t sz@ = size of block to be encrypted \ |
| 167 | * \ |
| 168 | * Returns: --- \ |
| 169 | * \ |
| 170 | * Use: Encrypts or decrypts a block with a block cipher in OFB \ |
| 171 | * mode: encryption and decryption are the same in OFB. \ |
| 172 | * The destination may be null to just churn the feedback \ |
| 173 | * round for a bit. The source may be null to use the \ |
| 174 | * cipher as a random data generator. \ |
| 175 | */ \ |
| 176 | \ |
| 177 | extern void pre##_ofbencrypt(pre##_ofbctx */*ctx*/, \ |
| 178 | const void */*src*/, void */*dest*/, \ |
| 179 | size_t /*sz*/); \ |
| 180 | \ |
| 181 | /* --- @pre_ofbrand@ --- * \ |
| 182 | * \ |
| 183 | * Arguments: @const void *k@ = pointer to key material \ |
| 184 | * @size_t sz@ = size of key material \ |
| 185 | * \ |
| 186 | * Returns: Pointer to generic random number generator interface. \ |
| 187 | * \ |
| 188 | * Use: Creates a random number interface wrapper around an \ |
| 189 | * OFB-mode block cipher. \ |
| 190 | */ \ |
| 191 | \ |
| 192 | extern grand *pre##_ofbrand(const void */*k*/, size_t /*sz*/); \ |
| 193 | \ |
| 194 | /* --- Generic cipher interface --- */ \ |
| 195 | \ |
| 196 | extern const gccipher pre##_ofb; |
| 197 | |
| 198 | /*----- That's all, folks -------------------------------------------------*/ |
| 199 | |
| 200 | #ifdef __cplusplus |
| 201 | } |
| 202 | #endif |
| 203 | |
| 204 | #endif |