Why Public Network?

Today IoT devices — IP cameras, smart meters, smart lights, smart sockets, smart fridges, etc. — are made available on the Internet through numerous cloud services, and while this solution currently works (no one can access your devices unless they hack the cloud provider) in many cases cloud does not add any meaningful functionality to what is already available through the device itself using standard protocols like HTTP, RTSP, MQTT.

The reason that we can not use this functionality without a cloud is two-fold: some of these protocols were never designed to work over the Internet and the Internet was never designed as a network for such devices. HTTP (without "S"), RTSP and many other protocols do not use encryption and public key exchange to initiate secure connection, and even if they did, bringing resource-constrained devices to the Internet will expose them to DDoS attacks and make it easy for adversaries to exploit zero-day vulnerabilities in the firmware.

The current solution to this problem (connecting these devices to the cloud) is quite an overkill for implementing secure communication channel. What we really need is the security on the network level so that IoT device vendors would not need to reimplement security for each of their devices. Solving this problem on a network level also improves users' privacy because they no longer need to rely on the cloud providers that often attract hackers by storing user data in one central location.