It seems transmitting the raw sensor data would make it tricky to do this securely. Would it be possible to encrypt the signal with some sort of hardware cipher?
They address the security possibilities in the paper:
> Our current implementation does not account
for security. However, to secure the wireless link between
the camera and reader, we can leverage the fact that our
digital core processes the PWM signal. Each wireless
camera can be assigned a unique pseudo random security
key. Based on this key, the camera’s digital core can
modulate the width of the PWM-encoded pixel value
using an XOR gate. The reader, which knows the security
key, can map the received data to the desired pixel values
by performing the analogous operation.
If the static image could be somehow "bankswitched", "shifted" or updated... I am thinking a huge one time pad. The problem is doing it power effeciently of course.
Thinking about, the main problem will be the penguin problem [1]. Which for a video is even worse as if a shape is moving, from seeing the pixels that are changing you can tell most of what is going on.
How about through a wall? That would make security applications in an apartment a bit less attractive, and I’m sure there are others. I wonder if encryption would be possible without much extra power overhead.
Analog encryption might be possible if the sender and receiver measure some common optical signal (assuming optically local security is what you're after).
There is a power source: the radio signal, but there's only microwatts available. Nevertheless, it's not impossible that there might be some clever solution to the problem, however, since the signal is analog that makes things a bit more challenging.
