A short way in. The full plain story is on truthbeam.com; the theory follows here.
Anyone can now fake a photo or video convincingly. So how do you prove that a recording is real, from a real moment, and not changed after the fact? Most of the time, today, you cannot.
PolieBotics is one answer to that question. At its heart is the Reality Kernel: an instrument that does not just capture a scene, but probes it in a closed loop, recording the scene's response to light it controls and commits to as it goes. The recording then carries its own evidence of how it was made, which is what is meant to make it hard to fake.
One instance of this idea has been demonstrated as a digital system: the Truth Beam. On a lab rig, a learned check tells genuine recordings from a trained forger's fakes on frames it had never seen, and the whole result is published so anyone can recompute it. It is an early, tightly scoped result, a floor rather than a ceiling. The broader instrument, continuous and analogue, is described and enabled in the filings, with its physical envelope still being characterised.
Two ways in. If you want the plain story, what it would be like to make, check, or fail to fake such a recording, and the kinds of thing it is for, start with the Truth Beam. If you want the theory, the instrument itself, what it can do, and why a recording made this way is hard to forge, read on into the Reality Kernel.