Function CheckEncryption

src/tests/test_network_crypto.cpp:217–246

static void CheckEncryption(MockNetworkSocketHandler *sending_socket_handler, MockNetworkSocketHandler *receiving_socket_handler)
{
	PacketType sent_packet_type{ 1 };
	uint64_t sent_value = 0x1234567890ABCDEF;
	std::set<PacketType> encrypted_packet_types;

	for (int i = 0; i < 10; i++) {
		Packet request(sending_socket_handler, sent_packet_type);
		request.Send_uint64(sent_value);

		auto [response, valid] = CreatePacketForReading(request, receiving_socket_handler);
		CHECK(valid);
		CHECK(response.Recv_uint64() == sent_value);

		encrypted_packet_types.insert(request.GetPacketType());
	}
	/*
	 * Check whether it looks like encryption has happened. This is done by checking the value
	 * of the packet type after encryption. If after a few iterations more than one encrypted
	 * value has been seen, then we know that some type of encryption/scrambling is happening.
	 *
	 * Technically this check could fail erroneously when 16 subsequent encryptions yield the
	 * same encrypted packet type. However, with encryption that byte should have random value
	 * value, so the chance of this happening are tiny given enough iterations.
	 * Roughly in the order of 2**((iterations - 1) * 8), which with 10 iterations is in the
	 * one-in-sextillion (10**21) order of magnitude.
	 */
	CHECK(encrypted_packet_types.size() != 1);

}

TEST_CASE("Encryption handling")
{