void Secp256k1PP::decrypt(Secret const& _k, bytes& io_text)
{
CryptoPP::ECIES<CryptoPP::ECP>::Decryptor d;
initializeDLScheme(_k, d);
if (!io_text.size())
{
io_text.resize(1);
io_text[0] = 0;
}
size_t clen = io_text.size();
bytes plain;
plain.resize(d.MaxPlaintextLength(io_text.size()));
DecodingResult r;
{
Guard l(x_rng);
r = d.Decrypt(m_rng, io_text.data(), clen, plain.data());
}
if (!r.isValidCoding)
{
io_text.clear();
return;
}
io_text.resize(r.messageLength);
io_text = std::move(plain);
}
static void pushLocation(bytes& o_code, uint32_t _locationValue)
{
o_code.push_back((byte)Instruction::PUSH4);
o_code.resize(o_code.size() + 4);
bytesRef r(&o_code[o_code.size() - 4], 4);
toBigEndian(_locationValue, r);
}
void Secp256k1PP::encryptECIES(Public const& _k, bytesConstRef _sharedMacData, bytes& io_cipher)
{
// interop w/go ecies implementation
auto r = KeyPair::create();
Secret z;
ecdh::agree(r.sec(), _k, z);
auto key = eciesKDF(z, bytes(), 32);
bytesConstRef eKey = bytesConstRef(&key).cropped(0, 16);
bytesRef mKeyMaterial = bytesRef(&key).cropped(16, 16);
CryptoPP::SHA256 ctx;
ctx.Update(mKeyMaterial.data(), mKeyMaterial.size());
bytes mKey(32);
ctx.Final(mKey.data());
bytes cipherText = encryptSymNoAuth(SecureFixedHash<16>(eKey), h128(), bytesConstRef(&io_cipher));
if (cipherText.empty())
return;
bytes msg(1 + Public::size + h128::size + cipherText.size() + 32);
msg[0] = 0x04;
r.pub().ref().copyTo(bytesRef(&msg).cropped(1, Public::size));
bytesRef msgCipherRef = bytesRef(&msg).cropped(1 + Public::size + h128::size, cipherText.size());
bytesConstRef(&cipherText).copyTo(msgCipherRef);
// tag message
CryptoPP::HMAC<SHA256> hmacctx(mKey.data(), mKey.size());
bytesConstRef cipherWithIV = bytesRef(&msg).cropped(1 + Public::size, h128::size + cipherText.size());
hmacctx.Update(cipherWithIV.data(), cipherWithIV.size());
hmacctx.Update(_sharedMacData.data(), _sharedMacData.size());
hmacctx.Final(msg.data() + 1 + Public::size + cipherWithIV.size());
io_cipher.resize(msg.size());
io_cipher.swap(msg);
}
void Secp256k1PP::decrypt(Secret const& _k, bytes& io_text)
{
auto& ctx = Secp256k1PPCtx::get();
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
CryptoPP::ECIES<CryptoPP::ECP>::Decryptor d;
#pragma GCC diagnostic pop
#pragma clang diagnostic pop
{
Guard l(ctx.x_params);
d.AccessKey().Initialize(ctx.m_params, secretToExponent(_k));
}
if (!io_text.size())
{
io_text.resize(1);
io_text[0] = 0;
}
size_t clen = io_text.size();
bytes plain;
plain.resize(d.MaxPlaintextLength(io_text.size()));
CryptoPP::DecodingResult r;
{
Guard l(ctx.x_rng);
r = d.Decrypt(ctx.m_rng, io_text.data(), clen, plain.data());
}
if (!r.isValidCoding)
{
io_text.clear();
return;
}
io_text.resize(r.messageLength);
io_text = std::move(plain);
}
static unsigned pushLiteral(bytes& o_code, u256 _literalValue)
{
unsigned br = max<unsigned>(1, bytesRequired(_literalValue));
o_code.push_back((byte)Instruction::PUSH1 + br - 1);
o_code.resize(o_code.size() + br);
for (unsigned i = 0; i < br; ++i)
{
o_code[o_code.size() - 1 - i] = (byte)(_literalValue & 0xff);
_literalValue >>= 8;
}
return br + 1;
}
bool Secp256k1PP::decryptECIES(Secret const& _k, bytesConstRef _sharedMacData, bytes& io_text)
{
// interop w/go ecies implementation
// io_cipher[0] must be 2, 3, or 4, else invalidpublickey
if (io_text.empty() || io_text[0] < 2 || io_text[0] > 4)
// invalid message: publickey
return false;
if (io_text.size() < (1 + Public::size + h128::size + 1 + h256::size))
// invalid message: length
return false;
Secret z;
if (!ecdh::agree(_k, *(Public*)(io_text.data() + 1), z))
return false; // Invalid pubkey or seckey.
auto key = ecies::kdf(z, bytes(), 64);
bytesConstRef eKey = bytesConstRef(&key).cropped(0, 16);
bytesRef mKeyMaterial = bytesRef(&key).cropped(16, 16);
bytes mKey(32);
CryptoPP::SHA256 ctx;
ctx.Update(mKeyMaterial.data(), mKeyMaterial.size());
ctx.Final(mKey.data());
bytes plain;
size_t cipherLen = io_text.size() - 1 - Public::size - h128::size - h256::size;
bytesConstRef cipherWithIV(io_text.data() + 1 + Public::size, h128::size + cipherLen);
bytesConstRef cipherIV = cipherWithIV.cropped(0, h128::size);
bytesConstRef cipherNoIV = cipherWithIV.cropped(h128::size, cipherLen);
bytesConstRef msgMac(cipherNoIV.data() + cipherLen, h256::size);
h128 iv(cipherIV.toBytes());
// verify tag
CryptoPP::HMAC<CryptoPP::SHA256> hmacctx(mKey.data(), mKey.size());
hmacctx.Update(cipherWithIV.data(), cipherWithIV.size());
hmacctx.Update(_sharedMacData.data(), _sharedMacData.size());
h256 mac;
hmacctx.Final(mac.data());
for (unsigned i = 0; i < h256::size; i++)
if (mac[i] != msgMac[i])
return false;
plain = decryptSymNoAuth(SecureFixedHash<16>(eKey), iv, cipherNoIV).makeInsecure();
io_text.resize(plain.size());
io_text.swap(plain);
return true;
}
bytes unpadded(bytes _b)
{
auto p = asString(_b).find_last_not_of((char)0);
_b.resize(p == string::npos ? 0 : (p + 1));
return _b;
}
bytes paddedRight(bytes _b, unsigned _l)
{
_b.resize(_l);
return _b;
}
