Oh, many years ago I had a baby monitor that included a pressure mat. If it detected no movement for a while (it was sensitive enough to detect breathing) it set off an alarm.
Although if such a thing exists today, it probably requires an app and a subscription. Enshitification.
"If you put a large switch in some cave somewhere, with a sign on it saying 'End-of-the- World Switch. PLEASE DO NOT TOUCH, the paint would't even have time to dry."
A private key would be built in to the camera. It would be stored in a way that's hard to get at, physically or in software (like the secure enclaves in phones).
The pics or videos are signed using the private key (again, this process needs to happen in a secure way without revealing the secret key).
The camera manufacturer publishes the matching public key. Anyone can use it to verify that the file matches the signature. But no one can sign a fake image unless they can get at the private key.
This would work even if the camera manufacturer no longer existed. The camera does need to ever be online.
The public/private key pairs are also part of what makes blockchains work, but for this process blockchains would add nothing.
Seriously. It's something about shampoo, hair conditioner, laundry detergent and laundry conditioner especially. The product type is printed as small as the dosage on med bottles.
Oh, many years ago I had a baby monitor that included a pressure mat. If it detected no movement for a while (it was sensitive enough to detect breathing) it set off an alarm.
Although if such a thing exists today, it probably requires an app and a subscription. Enshitification.