lib/arcfour.h

   1 /* arcfour.h --- The arcfour stream cipher
   2  * Copyright (C) 2000-2005, 2009-2025 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 ARCFOUR_H
  22 #define ARCFOUR_H
  23
  24 #include <stddef.h>
  25 #include <stdint.h>
  26
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31
  32 #define ARCFOUR_SBOX_SIZE 256
  33
  34 typedef struct
  35 {
  36   char sbox[ARCFOUR_SBOX_SIZE];
  37   uint8_t idx_i, idx_j;
  38 } arcfour_context;
  39
  40 /* Apply ARCFOUR stream to INBUF placing the result in OUTBUF, both of
  41    LENGTH size.  CONTEXT must be initialized with arcfour_setkey
  42    before this function is called. */
  43 extern void
  44 arcfour_stream (arcfour_context * context,
  45                 const char *inbuf, char *restrict outbuf, size_t length);
  46
  47 /* Initialize CONTEXT using encryption KEY of KEYLEN bytes.  KEY
  48    should be 40 bits (5 bytes) or longer.  The KEY cannot be zero
  49    length.  */
  50 extern void
  51 arcfour_setkey (arcfour_context * context, const char *key, size_t keylen);
  52
  53
  54 #ifdef __cplusplus
  55 }
  56 #endif
  57
  58 #endif /* ARCFOUR_H */