The article says it has a CPU, therefore in theory it can check digital signatures.
That said, I don't see why would it need to be passive if it's in a light bulb, or any other device that can be actuated. It'll need more energy to do whatever you tell it to, so it can also use that energy to actively power the CPU.
That said, I don't see why would it need to be passive if it's in a light bulb, or any other device that can be actuated. It'll need more energy to do whatever you tell it to, so it can also use that energy to actively power the CPU.