C++ bytes::resize方法代码示例

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;
 }