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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* 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 2 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 *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* 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, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#include "rc4encryptor.h"
namespace mse
{
static void swap(Uint8 & a,Uint8 & b)
{
Uint8 tmp = a;
a = b;
b = tmp;
}
static Uint8 rc4_enc_buffer[bt::MAX_MSGLEN];
RC4::RC4(const Uint8* key,Uint32 size) : i(0),j(0)
{
// initialize state
for (Uint32 t = 0;t < 256;t++)
s[t] = t;
j = 0;
for (Uint32 t=0;t < 256;t++)
{
j = (j + s[t] + key[t % size]) & 0xff;
swap(s[t],s[j]);
}
i = j = 0;
}
RC4::~RC4()
{
}
void RC4::process(const Uint8* in,Uint8* out,Uint32 size)
{
for (Uint32 k = 0;k < size;k++)
{
out[k] = process(in[k]);
}
}
Uint8 RC4::process(Uint8 b)
{
i = (i + 1) & 0xff;
j = (j + s[i]) & 0xff;
swap(s[i],s[j]);
Uint8 tmp = s[ (s[i] + s[j]) & 0xff];
return tmp ^ b;
}
RC4Encryptor::RC4Encryptor(const bt::SHA1Hash & dk,const bt::SHA1Hash & ek)
: enc(ek.getData(),20),dec(dk.getData(),20)
{
Uint8 tmp[1024];
enc.process(tmp,tmp,1024);
dec.process(tmp,tmp,1024);
}
RC4Encryptor::~RC4Encryptor()
{}
void RC4Encryptor::decrypt(Uint8* data,Uint32 len)
{
dec.process(data,data,len);
}
const Uint8* RC4Encryptor::encrypt(const Uint8* data,Uint32 len)
{
enc.process(data,rc4_enc_buffer,len);
return rc4_enc_buffer;
}
void RC4Encryptor::encryptReplace(Uint8* data,Uint32 len)
{
enc.process(data,data,len);
}
}
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