mdw@git.distorted.org.uk Git - disorder/blob - lib/arcfour.h

   1 /* arcfour.h --- The arcfour stream cipher
   2  * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
   3  *    Free Software Foundation, Inc.
   4  *
   5  * This file is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published
   7  * by the Free Software Foundation; either version 2, or (at your
   8  * option) any later version.
   9  *
  10  * This file is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this file; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA.
  19  *
  20  */
  21 /** @file lib/arcfour.h
  22  * @brief Arcfour (RC4-compatible) stream cipher implementation
  23  */
  24
  25 /* Code from Libgcrypt adapted for gnulib by Simon Josefsson. */
  26
  27 #ifndef ARCFOUR_H
  28 # define ARCFOUR_H
  29
  30 # include <stddef.h>
  31 # include <stdint.h>
  32
  33 #define ARCFOUR_SBOX_SIZE 256
  34
  35 /** @brief Context structture for Arcfour stream cipher */
  36 typedef struct
  37 {
  38   char sbox[ARCFOUR_SBOX_SIZE];
  39   uint8_t idx_i, idx_j;
  40 } arcfour_context;
  41
  42 /* Apply ARCFOUR stream to INBUF placing the result in OUTBUF, both of
  43    LENGTH size.  CONTEXT must be initialized with arcfour_setkey
  44    before this function is called. */
  45 extern void
  46 arcfour_stream (arcfour_context * context,
  47                 const char *inbuf, char *outbuf, size_t length);
  48
  49 /* Initialize CONTEXT using encryption KEY of KEYLEN bytes.  KEY
  50    should be 40 bits (5 bytes) or longer.  The KEY cannot be zero
  51    length.  */
  52 extern void
  53 arcfour_setkey (arcfour_context * context, const char *key, size_t keylen);
  54
  55 #endif /* ARCFOUR_H */