Great point on the analogue hack. But I think it's a perfect-is-enemy-of-good situation. There is currently no such thing as digitally verifiable media. If such a thing existed, it would at least partially shove the cat back into the bag (maybe people would abuse the cameras with the HSMs in this way, but its one step better than having all images with no verifiability). Whats more, Photoshop has existed for 25 years - and convincing Hollywood SFX for 30+ - so clearly it is deep fakes specifically that are the nascent threat. Doesn't HSM at least help address low effort deep fakes from people without HSM enabled cameras? Also, you could put in a depth range sensor and make the depth reading part of the signed payload.