- Decision support for devices answers whether an incoming friendship, sensor-read, or control request is allowed.
- Provisioning for owners lets owners answer new questions and manage the rules used for later decisions.
Fail-closed flow
Devices cache decisions to avoid a network round trip for every operation. When an owner changes rules, the provisioning server instructs affected devices to clear cached answers.What a rule can constrain
- requester identity/domain;
- device, data source, node, and field;
- sensor field categories and time range;
- control parameter/action;
- service, device, or user token;
- time and contextual restrictions supported by the provider.
Implementation rules
- Deny unknown situations by default.
- Cache the full constrained decision, not a broad boolean.
- Put an expiry on cached permissions where policy requires it.
- Authenticate provisioning messages and protect them end-to-end when sensitive.
- Make rule updates and cache clears idempotent.
- Keep an audit trail of owner decision, requester, resource, constraints, and outcome.
- Provide a safe offline policy for devices that cannot reach provisioning.