/*

This file is part of cpp-ethereum.

cpp-ethereum 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 3 of the License, or

(at your option) any later version.

cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.

*/

/** @file AES.cpp

* @author Alex Leverington <nessence@gmail.com>

* @date 2014

*/

#include "AES.h"

#include <libdevcore/Common.h>

#include "CryptoPP.h"

using namespace std;

using namespace dev;

using namespace dev::crypto;

using namespace dev::crypto::aes;

using namespace CryptoPP;

struct aes::Aes128Ctr

{

Aes128Ctr(h128 _k)

{

mode.SetKeyWithIV(_k.data(), sizeof(h128), Nonce::get().data());

}

CTR_Mode<AES>::Encryption mode;

};

Stream::Stream(StreamType, h128 _ckey):

m_cSecret(_ckey)

{

cryptor = new Aes128Ctr(_ckey);

}

Stream::~Stream()

{

delete cryptor;

}

void Stream::update(bytesRef)

{

}

size_t Stream::streamOut(bytes&)

{

return 0;

}

bytes dev::aesDecrypt(bytesConstRef _ivCipher, std::string const& _password, unsigned _rounds, bytesConstRef _salt)

{

bytes pw = asBytes(_password);

if (!_salt.size())

_salt = &pw;

bytes target(64);

CryptoPP::PKCS5_PBKDF2_HMAC<CryptoPP::SHA256>().DeriveKey(target.data(), target.size(), 0, pw.data(), pw.size(), _salt.data(), _salt.size(), _rounds);

try

{

CryptoPP::AES::Decryption aesDecryption(target.data(), 16);

auto cipher = _ivCipher.cropped(16);

auto iv = _ivCipher.cropped(0, 16);

CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption(aesDecryption, iv.data());

std::string decrypted;

CryptoPP::StreamTransformationFilter stfDecryptor(cbcDecryption, new CryptoPP::StringSink(decrypted));

stfDecryptor.Put(cipher.data(), cipher.size());

stfDecryptor.MessageEnd();

return asBytes(decrypted);

}

catch (exception const& e)

{

cerr << e.what() << endl;

return bytes();

}

}