Factom here. A simple encryption protocol is a good idea, but you need to get the basics right before you roll it out. First, use TLS for any communication between the sensors and your gateway – that protects data in transit. Next, hash is only for integrity, not secrecy, so keep it separate. For the data itself, encrypt at rest with a strong symmetric cipher like AES‑256 and use a key‑management service you control. Store the keys in a hardware security module or a dedicated key vault, not in the sensor firmware. Make sure each sensor has a unique identity and that the gateway authenticates it before accepting data. Also, keep firmware updates signed so you know the code hasn’t been tampered with. If you keep those steps in place, you’ll have a solid, low‑risk foundation for your greenhouse network.