lib/arctwo.h

   1 /* arctwo.h --- The arctwo block cipher
   2  * Copyright (C) 2000-2003, 2005, 2009-2024 Free Software Foundation, Inc.
   3  *
   4  * This file is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License as
   6  * published by the Free Software Foundation; either version 2.1 of the
   7  * License, or (at your option) any later version.
   8  *
   9  * This file is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16  *
  17  */
  18
  19 /* Code from Libgcrypt adapted for gnulib by Simon Josefsson. */
  20
  21 #ifndef ARCTWO_H
  22 # define ARCTWO_H
  23
  24 # include <stddef.h>
  25 # include <stdint.h>
  26
  27 typedef struct
  28 {
  29   uint16_t S[64];
  30 } arctwo_context;
  31
  32 #define ARCTWO_BLOCK_SIZE 8
  33
  34 /* Initialize CONTEXT using KEY of KEYLEN length.  If
  35    EFFECTIVE_KEYLEN, truncate the key (using a special algorithm) to
  36    only be of EFFECTIVE_KEYLEN bits.  Normally, you use
  37    EFFECTIVE_KEYLEN of 0, but see RFC 2268 for more information. */
  38 void
  39 arctwo_setkey_ekb (arctwo_context *context,
  40                    size_t keylen, const char *key, size_t effective_keylen);
  41
  42 #define arctwo_setkey(context,keylen,key) \
  43   arctwo_setkey_ekb (context, keylen, key, 8 * (keylen))
  44
  45 /* Encrypt INBUF of size LENGTH into OUTBUF.  LENGTH must be a
  46    multiple of ARCTWO_BLOCK_SIZE.  CONTEXT hold the encryption key,
  47    and must have been initialized with arctwo_setkey or
  48    arctwo_setkey_ekb. */
  49 extern void
  50 arctwo_encrypt (arctwo_context *context, const char *inbuf,
  51                 char *restrict outbuf, size_t length);
  52
  53 /* Decrypt INBUF of size LENGTH into OUTBUF.  LENGTH must be a
  54    multiple of ARCTWO_BLOCK_SIZE.  CONTEXT hold the decryption key,
  55    and must have been initialized with arctwo_setkey or
  56    arctwo_setkey_ekb. */
  57 extern void
  58 arctwo_decrypt (arctwo_context *context, const char *inbuf,
  59                 char *restrict outbuf, size_t length);
  60
  61 #endif /* ARCTWO_H */