u/BossReady309

One thing that confuses me is how a private or secure connection can exist on top of a public internet system. If the infrastructure is shared globally, how does it still create isolation and privacy for specific users or organizations? Is it mainly encryption, software-based separation, or virtual pathways like VPN and tunneling services such as tunnil net And how strong is this separation in real-world use? Can it ever be fully isolated, or is it always part of the same underlying public network? I am trying to understand how these systems make online communication feel private and secure despite using shared infrastructure.