2009-06-13 05:38:31 -06:00
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/*
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* Copyright (c) 1996, 2003 VIA Networking Technologies, Inc.
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* File: rc4.c
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*
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* Purpose:
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*
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* Functions:
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*
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* Revision History:
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*
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* Author: Kyle Hsu
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*
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* Date: Sep 4, 2002
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*
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*/
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#include "rc4.h"
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2013-02-25 18:32:51 -07:00
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void rc4_init(PRC4Ext pRC4, u8 * pbyKey, unsigned int cbKey_len)
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2009-06-13 05:38:31 -06:00
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{
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2010-05-17 18:34:01 -06:00
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unsigned int ust1, ust2;
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unsigned int keyindex;
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unsigned int stateindex;
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2013-02-25 18:32:51 -07:00
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u8 * pbyst;
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2010-05-17 18:34:01 -06:00
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unsigned int idx;
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2009-06-13 05:38:31 -06:00
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2010-03-29 05:26:46 -06:00
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pbyst = pRC4->abystate;
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pRC4->ux = 0;
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pRC4->uy = 0;
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for (idx = 0; idx < 256; idx++)
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2013-02-25 18:32:51 -07:00
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pbyst[idx] = (u8)idx;
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2010-03-29 05:26:46 -06:00
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keyindex = 0;
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stateindex = 0;
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for (idx = 0; idx < 256; idx++) {
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ust1 = pbyst[idx];
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stateindex = (stateindex + pbyKey[keyindex] + ust1) & 0xff;
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ust2 = pbyst[stateindex];
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2013-02-25 18:32:51 -07:00
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pbyst[stateindex] = (u8)ust1;
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pbyst[idx] = (u8)ust2;
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2010-03-29 05:26:46 -06:00
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if (++keyindex >= cbKey_len)
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keyindex = 0;
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}
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2009-06-13 05:38:31 -06:00
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}
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2010-05-17 18:34:01 -06:00
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unsigned int rc4_byte(PRC4Ext pRC4)
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{
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unsigned int ux;
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unsigned int uy;
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unsigned int ustx, usty;
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2013-02-25 18:32:51 -07:00
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u8 * pbyst;
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2009-06-13 05:38:31 -06:00
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2010-03-29 05:26:46 -06:00
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pbyst = pRC4->abystate;
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ux = (pRC4->ux + 1) & 0xff;
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ustx = pbyst[ux];
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uy = (ustx + pRC4->uy) & 0xff;
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usty = pbyst[uy];
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pRC4->ux = ux;
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pRC4->uy = uy;
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2013-02-25 18:32:51 -07:00
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pbyst[uy] = (u8)ustx;
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pbyst[ux] = (u8)usty;
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2009-06-13 05:38:31 -06:00
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2010-03-29 05:26:46 -06:00
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return pbyst[(ustx + usty) & 0xff];
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2009-06-13 05:38:31 -06:00
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}
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2013-02-25 18:32:51 -07:00
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void rc4_encrypt(PRC4Ext pRC4, u8 * pbyDest,
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u8 * pbySrc, unsigned int cbData_len)
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2009-06-13 05:38:31 -06:00
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{
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2010-05-17 18:34:01 -06:00
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unsigned int ii;
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2010-03-29 05:26:46 -06:00
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for (ii = 0; ii < cbData_len; ii++)
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pbyDest[ii] = (u8)(pbySrc[ii] ^ rc4_byte(pRC4));
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2009-06-13 05:38:31 -06:00
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}
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