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/*
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 EC.cpp
* @author Alex Leverington <nessence@gmail.com>
* @date 2014
*
* Shared EC classes and functions.
*/
#pragma warning(push)
#pragma warning(disable:4100 4244)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wdelete-non-virtual-dtor"
#pragma GCC diagnostic ignored "-Wextra"
#include <files.h>
#pragma warning(pop)
#pragma GCC diagnostic pop
#include "CryptoPP.h"
#include "SHA3.h"
#include "EC.h"
// CryptoPP and dev conflict so dev and pp namespace are used explicitly
using namespace std;
using namespace dev;
using namespace dev::crypto;
using namespace CryptoPP;
void dev::crypto::encrypt(Public const& _key, bytes& _plain)
{
ECIES<ECP>::Encryptor e;
e.AccessKey().AccessGroupParameters().Initialize(pp::secp256k1());
e.AccessKey().SetPublicElement(pp::PointFromPublic(_key));
size_t plen = _plain.size();
std::string c;
c.resize(e.CiphertextLength(plen));
e.Encrypt(pp::PRNG(), _plain.data(), plen, (byte*)c.data());
_plain.resize(c.size());
memcpy(_plain.data(), c.data(), c.size());
}
void dev::crypto::decrypt(Secret const& _k, bytes& _c)
{
CryptoPP::ECIES<CryptoPP::ECP>::Decryptor d;
d.AccessKey().AccessGroupParameters().Initialize(pp::secp256k1());
d.AccessKey().SetPrivateExponent(pp::ExponentFromSecret(_k));
size_t clen = _c.size();
std::string p;
p.resize(d.MaxPlaintextLength(_c.size()));
DecodingResult r = d.Decrypt(pp::PRNG(), _c.data(), clen, (byte*)p.data());
assert(r.messageLength);
_c.resize(r.messageLength);
memcpy(_c.data(), p.data(), _c.size());
}
SecretKeyRef::SecretKeyRef()
{
secp256k1_start();
static std::mt19937_64 s_eng(time(0));
std::uniform_int_distribution<uint16_t> d(0, 255);
for (int i = 0; i < 100; ++i)
{
for (unsigned i = 0; i < 32; ++i)
m_secret[i] = (byte)d(s_eng);
/// todo: check key validity w/cryptopp
KeyPair ret(m_secret);
if (ret.address())
break;
}
/// todo: throw exception if key doesn't happen (or run forever?)
/// todo: ^ also in KeyPair::create()
}
Public SecretKeyRef::pub() const
{
Public p;
pp::PublicFromExponent(pp::ExponentFromSecret(m_secret), p);
return p;
}
Address SecretKeyRef::address() const
{
return dev::right160(dev::sha3(bytesConstRef(pub().data(), 64)));
}