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   Unix SMB/CIFS implementation.

   An implementation of arc4.

   Copyright (C) Jeremy Allison 2005.
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   GNU General Public License for more details.
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "includes.h"

 Initialize state for an arc4 crypt/decrpyt.
 arc4 state is 258 bytes - last 2 bytes are the index bytes.

void smb_arc4_init(unsigned char arc4_state_out[258], const unsigned char *key, size_t keylen)
      size_t ind;
      unsigned char j = 0;

      for (ind = 0; ind < 256; ind++) {
            arc4_state_out[ind] = (unsigned char)ind;

      for( ind = 0; ind < 256; ind++) {
            unsigned char tc;

            j += (arc4_state_out[ind] + key[ind%keylen]);

            tc = arc4_state_out[ind];
            arc4_state_out[ind] = arc4_state_out[j];
            arc4_state_out[j] = tc;
      arc4_state_out[256] = 0;
      arc4_state_out[257] = 0;

 Do the arc4 crypt/decrpyt.
 arc4 state is 258 bytes - last 2 bytes are the index bytes.

void smb_arc4_crypt(unsigned char arc4_state_inout[258], unsigned char *data, size_t len)
      unsigned char index_i = arc4_state_inout[256];
      unsigned char index_j = arc4_state_inout[257];
        size_t ind;

      for( ind = 0; ind < len; ind++) {
            unsigned char tc;
            unsigned char t;

            index_j += arc4_state_inout[index_i];

            tc = arc4_state_inout[index_i];
            arc4_state_inout[index_i] = arc4_state_inout[index_j];
            arc4_state_inout[index_j] = tc;

            t = arc4_state_inout[index_i] + arc4_state_inout[index_j];
            data[ind] = data[ind] ^ arc4_state_inout[t];

      arc4_state_inout[256] = index_i;
      arc4_state_inout[257] = index_j;

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