Glossary
Constrained Device
A constrained device operates with meaningfully less processing power, memory, or battery capacity than a typical server or personal computer — a sensor, a small embedded controller, a battery-powered peripheral. Cryptographic operations that a server performs without a second thought can be genuinely expensive on hardware this limited, sometimes prohibitively so for the device's power budget or response-time requirements.
This forces real design tradeoffs rather than simply applying the same authentication and authorization approach used elsewhere: lighter-weight cryptography, less frequent re-authentication, or delegating heavier verification work to a nearby, more capable intermediary rather than performing it on the constrained device itself.