67 lines
1.6 KiB
C++
67 lines
1.6 KiB
C++
/*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
* Copyright 2015 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#include "arc4.hpp"
|
|
|
|
#include <algorithm>
|
|
#include <numeric>
|
|
|
|
using util::crypto::ARC4;
|
|
|
|
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
ARC4::ARC4 (const uint8_t *restrict key, size_t len):
|
|
x (0),
|
|
y (0)
|
|
{
|
|
std::iota (S.begin (), S.end (), 0);
|
|
|
|
for (size_t i = 0, j = 0; i < 256; ++i) {
|
|
j = (j + S[i] + key[i % len]) % 256;
|
|
std::swap (S[i], S[j]);
|
|
}
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
void
|
|
ARC4::discard (size_t len)
|
|
{
|
|
while (len--)
|
|
get ();
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
void
|
|
ARC4::generate (uint8_t *restrict dst, size_t len)
|
|
{
|
|
std::generate_n (dst, len, [this] (void) { return get (); });
|
|
}
|
|
|
|
|
|
//-----------------------------------------------------------------------------
|
|
uint8_t
|
|
ARC4::get (void)
|
|
{
|
|
x = (x + 1) % 256;
|
|
y = (y + S[x]) % 256;
|
|
|
|
std::swap (S[x], S[y]);
|
|
|
|
return S[(S[x] + S[y]) % 256];
|
|
}
|