How do we know evidence is valid in a court case? Chain of custody and documentation. Add to that some commitment scheme and trusted time-stamping and publish i

How do we know evidence is valid in a court case? Chain of custody and documentation. Add to that some commitment scheme and trusted time-stamping and publish in real time and you are most of the way there to extremely veridical publishing. But the main problem is the people most vulnerable to fake media are already bamboozled by bad Photoshop jobs. I don't see how any signing scheme will help.