What are the three domains of an end-to-end IoT software architecture, and why is it a mistake to design any one of them alone?
Software architectures for IoT devices, for the gateway, and for the cloud — three tiers with three different sets of constraints, joined by security properties that only exist if all three cooperate.
* Device, gateway and cloud have distinct software responsibilities; end-to-end protection spans their boundaries. *
The three domains:
- SW architecture for IoT devices — the constrained tier. Typically layered as a drivers layer (I/O, timers, power management), a framework layer (runtime, sensors, storage) and an app layer (security, communication, data processing), sitting on compute, network and storage hardware.
- SW architecture for the gateway — the aggregating tier, on real hardware with a real OS.
- SW architecture for the cloud — data analytics, control systems, big data, container orchestration.
They cannot be designed independently, because the security properties are drawn across the tiers rather than inside them. The same diagram labels several distinct security concerns at different heights:
- Execution security and device-level security — inside the endpoint.
- Wireless communication security — on the link between device and cloud.
- Cloud-level security — in the backend.
- End-to-end security and end-to-end data encryption — spanning the whole height of the stack.
The last two are the reason for the "end-to-end" phrasing. An encrypted radio link plus a hardened cloud does not give you end-to-end encryption; it gives you two secure hops with a gateway in the middle that can read everything. Whether a reading is confidential from the sensor to the dashboard is a property of the joint design, and no single tier's architect can deliver it.
Tip: "end-to-end" is a claim about the gaps between the boxes. If a design only secures the boxes, it is not end-to-end.
Go deeper:
RFC 7452 — Smart object architecture — compares device-to-device, gateway and cloud patterns and their trust boundaries.