The sensor already uses phase detection autofocus. You can create a depth map out of it. iPhone X used its dual cameras and that phase data for depth maps.
replyThey could use the camera aperture to take a second photo and calculate blur.
replyIf that became popular, the AIs would learn how to generate a realistic depth map along with any generated image.
replyHow would that work? I thought the premise here is that you can fool the apple camera by taking a (very carefully aligned) picture of a still image (printed out).
replyA depth map from the apple camera (again, signed) would show that the entire image had the same distance from the camera.
You're right. I think my comment above doesn't make sense - it wouldn't help in this case.
replyThe photos are cryptographically signed in the apple image pipeline so it's not as simple as just AI generating something. That said, I can't see how this is any different to all the other times we have embedded crypto keys in consumer hardware where eventually someone finds a way to extract the key and the whole thing is busted open.
replyGiven the whole private cloud bit, I am assuming they keep the private keys server side and never let them out.
replyI think there's a chain of trust. The sensor signs raws, and the private cloud takes signed raws, does minimal processing so they're at least coherent, and re signs that output (maybe even including the original signed raw as well in the image file).
replyHow would the server know that the request is coming from a real iPhone?
replyThis is a pretty standard application of trusted computing and can be done entirely on the iPhone. A server would only possibly be needed for anonymization (while retaining key revocation capabilities if a key does end up leaking), but there are serverless ways to do even that (TPMs have supported these for a while now).
It wouldn't, but you could validate that a particular picture was created at a particular time, and had not changed, for example, especially with metadata that you may not want to share but that establishes certain parameters like gps coordinates. A lock, rather than an end-to-end pixel signature, which shows what was contemporaneous rather than exact provenance. If an event happened on day 0000-00-00 00:00:00am, but your photo was taken at some other time, it casts doubt.
replyI think a big part of validation for things like these are just "could it have been modified since Z event happened", because Z was not something people paid attention to before.
That's a good point, You might still be able to trick the cloud to sign your photos, but that's something they could patch in updates without losing control of the key. They could have the server only sign photos taken on the latest ios version.
replyAnd honestly you could have a similar antitampering oracle that was at least obscured, in terms of "we've detected tampering but won't tell you how or why", which is frustrating but I have to imagine that 99.9%+ of images are clean.
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replyEven simpler, a 3D printed relief with an image "stamped" on it, now you effectively have a 3D image.
reply…and the PDAF data will show how shallow it is.
reply... don't make it so shallow then. Perfectly possible in a consumer-friendly 3D printer for a face or even human body if you have lots of time for the prints.
replyYou’re well on the way to 1:1 replicas at this point. Next you’ll need to match the thermal signature and the exact weather in the sky for the time at that location.
replySounds like Rincewind's spell from the Octavo.
replyThen take and sign a one-second video and you’re adding a few orders of magnitude of complexity again.
replybut what are we really trying to solve here. you're suggesting a helluvalota work for what purpose?
replyThe 'ol "analog hole". Never been able to patch that gap.
replyYes, if your adversary can generate a high-fidelity 3D moving replica of a scene, they can deceive you that it’s real. But can they really?
replyAnd what if you take a picture across a IR-filtered window?
replyThen you won’t be able to prove it was a genuine photograph? That sounds like the right failure mode.
replyThat's a cool idea.
replyPretty sure it does that already.
replyOne can 3d-print the AI generated image and photograph that. /s
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