keepassxc/src/format/KeePass2RandomStream.cpp
2012-04-18 22:08:22 +02:00

80 lines
2.2 KiB
C++

/*
* Copyright (C) 2010 Felix Geyer <debfx@fobos.de>
*
* 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 or (at your option)
* version 3 of the License.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "KeePass2RandomStream.h"
#include "crypto/CryptoHash.h"
#include "format/KeePass2.h"
KeePass2RandomStream::KeePass2RandomStream(const QByteArray& key)
: m_cipher(SymmetricCipher::Salsa20, SymmetricCipher::Stream, SymmetricCipher::Encrypt,
CryptoHash::hash(key, CryptoHash::Sha256), KeePass2::INNER_STREAM_SALSA20_IV)
, m_offset(0)
{
}
QByteArray KeePass2RandomStream::randomBytes(int size)
{
QByteArray result;
int bytesRemaining = size;
while (bytesRemaining > 0) {
if (m_buffer.size() == m_offset) {
loadBlock();
}
int bytesToCopy = qMin(bytesRemaining, m_buffer.size() - m_offset);
result.append(m_buffer.mid(m_offset, bytesToCopy));
m_offset += bytesToCopy;
bytesRemaining -= bytesToCopy;
}
return result;
}
QByteArray KeePass2RandomStream::process(const QByteArray& data)
{
QByteArray randomData = randomBytes(data.size());
QByteArray result;
result.resize(data.size());
for (int i = 0; i < data.size(); i++) {
result[i] = data[i] ^ randomData[i];
}
return result;
}
void KeePass2RandomStream::processInPlace(QByteArray& data)
{
QByteArray randomData = randomBytes(data.size());
for (int i = 0; i < data.size(); i++) {
data[i] = data[i] ^ randomData[i];
}
}
void KeePass2RandomStream::loadBlock()
{
Q_ASSERT(m_offset == m_buffer.size());
m_buffer.fill('\0', m_cipher.blockSize());
m_cipher.processInPlace(m_buffer);
m_offset = 0;
}