LINU:Modify Ethernet/WiFi so only certain marked data packets can be uploaded

I am using Linux. I want you to modify Ethernet/WiFi so only certain data packets can be uploaded. Let's say that a computer gets hacked via web browser, but the WiFi/Ethernet only allows certain data packets to be uploaded. You can't predict what data might get downloaded to your computer, so I don't try to protect against that. If hackers want to steal your data, though, they need to upload it somehow. So for uploads... there should be some kind of a process which cannot be terminated... and this process would filter all data uploaded to make sure it is marked in a certain way... Thus, you know that this is your data, because only YOU know how to mark it.. The hacker wouldn't know how to mark the data they are uploading, and thus, it would get rejected and never get uploaded in the first place. Perhaps each data packet has a certain code sent before it, or attached to it. These codes don't need to be uploaded over the web, but just checked by this filter software, before being sent off to the WiFI/Ethernet driver to be uploaded. Or perhaps this would be implemented by editing the WiFi/Ethernet driver itself. I don't know precisely how to implement it... but I hope you understand what I'm asking for here. Thanks