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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2013 Nils Maier
*
* 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
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "InternalARC4Encryptor.h"
namespace aria2 {
void ARC4Encryptor::init(const unsigned char* key, size_t keyLength)
{
j = 0;
for (auto& c : state_) c = j++;
j = 0;
for (i = 0; i < sizeof(state_); ++i) {
j = (j + state_[i] + key[i % keyLength]) & 0xff;
auto tmp = state_[i];
state_[i] = state_[j];
state_[j] = tmp;
}
i = j = 0;
}
void ARC4Encryptor::encrypt(size_t len, unsigned char* out,
const unsigned char* in)
{
for (auto c = 0u; c < len; ++c) {
i = (i + 1) & 0xff;
j = (j + state_[i]) & 0xff;
auto sj = state_[i];
auto si = state_[i] = state_[j];
state_[j] = sj;
out[c] = in[c] ^ state_[(si + sj) & 0xff];
}
}
} // namespace aria2
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