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Apple Reference Image: A New Approach for Verified Photography

security.apple.com

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Re: Apple Reference Image: A New Approach for Verified Photography

#321

Earlier quoted context omitted.

Claim 7 in this patent application describes how depth sensors are used as part of an image authentication process, which would make such a workaround more difficult: https://image-ppubs.uspto.gov/dirsearch-public/print/downloa... The Apple Reference Image feature is here launched on iPhone 18 Pro and iPhone 18 Pro Max that both have built-in LiDAR sensors that could be used for this process.

Apple's current implementation doesn't integrate LiDAR. And LiDAR wouldn't be enough here, it's trivial to block the projector and hide the dot pattern. No dot pattern = iPhone thinks the object is far away, which is what happens in landscape photos. A better fix is to take photos with all three iPhone cameras simultaneously, ideally as a 2-3s video, and use the parallax/multiple perspectives to extract depth informa…

> A better fix is to take photos with all three iPhone cameras simultaneously, ideally as a 2-3s video, and use the parallax/multiple perspectives to extract depth information.

I think iPhones already do this (although without taking multiple seconds of video). iOS is capable of generating pretty accurate depth data even on devices with no LiDAR unit.

Re: Apple Reference Image: A New Approach for Verified Photography

#322
post #269

Earlier quoted context omitted.

> This is really clever from Apple. The journalist use case is just the PR story. This will be really useful for identity verification and insurance apps, and has the potential to shift from "you need a smartphone to be able to live normally" to "you need an iPhone to be able to live normally". You have it all wrong. Apple Reference Image is not an id system; it's primarily a way to attest that the pixels recorded by…

> You have it all wrong. > Apple Reference Image is not an id system GP does not have it all wrong. A company desiring you to prove your identity often asks for a photograph of your government ID. Now that this is easily faked, it is reasonable to expect that the company will ask for a verifiably authentic photograph of your government ID. That the Apple Reference Image itself is not traceable to the device/user is b…

> Now that this is easily faked, it is reasonable to expect that the company will ask for a verifiably authentic photograph of your government ID.

The image will be authentic, but an authentic image of a fake id isn't useful to them.

Also--only two iPhone models support this technology. It'll be years before the DMV or whoever could count on enough adoption before they could support it.

Re: Apple Reference Image: A New Approach for Verified Photography

#323

Earlier quoted context omitted.

Apple gets the device-signed image and replaces with a PCC signature to preserve anonymity. > The final reference image is instead signed by Apple’s signing service, after validation by PCC. So, if compelled, Apple could theoretically tell someone if two images came from the same camera.

> So, if compelled, Apple could theoretically tell someone if two images came from the same camera. No they couldn't. If you generate two SSH key pairs on your laptop, there's no way to confirm they were created on the same machine. There's no device identifying data in a reference image, which is the point. The factory signature, the image sensor key, the Secure Enclave Processor key and all of the signing that take…

I stand corrected. If it’s truly only the signatures and zero other identifying info, then yes you’re as secure as the underlying algorithm. I think they implied there are multiple device-originated signatures for different parts of the data, this may open some possibilities for cryptanalysis

Re: Apple Reference Image: A New Approach for Verified Photography

#324
post #8
post #4

Earlier quoted context omitted.

Sony's analogous solution ( https://authenticity.sony.net/camera/en-us/ ) claims 3d depth information is built in, I'm sure Apple could do the same given at least some iPhone models have LiDAR on the back

This would work for close up shots taken on iPhone, but not landscape shots. The infrared dots the iPhone LiDAR projects are too weak to appear over long distances. Also the dots can be trivially blocked by putting your finger over the sensor, sometimes improving photo quality. I do this frequently when I want to take a photo through a window. The absence of the dot matrix tells the iPhone to focus on the background…

What they could do instead is record a video while taking a photo, the subtle movements (at least if handheld) might have enough information to get an approximation of depth (parallax).

Re: Apple Reference Image: A New Approach for Verified Photography

#326
post #312

Earlier quoted context omitted.

> If they can verify an Apple Reference Image they can verify an NFC document Interfacing with images is easy. Interfacing with NFC takes work. I have experienced precisely zero identity-verification workflows which NFC'd anything, and that includes my banks, which could easily ask for my debit card's NFC but don't.

Counterpoint: all of the identity-verification flows I have experienced in the last few years used NFC to read the chip in my identity documents - from car rental apps to my bank doing KYC. If anything, verifying NFC is easier than images. Asking the chip in my identity card to provide a cryptographically-signed "This document belongs to Jane Doe" request is a handful of lines of code. Doing the same with images? Goo…

Cool! Where are you geographically? I’m mostly in North America, Europe and South Asia.

Re: Apple Reference Image: A New Approach for Verified Photography

#328
post #3

Apple doesn't address the modified photo replay situation, where you take a picture of an already edited image. Photoshop / AI-gen an image -> display on a high-resolution monitor -> photograph the monitor with iPhone 18 Pro -> valid Apple Reference image. To get valid reference photos, you can go to the actual physical location, put the iPhone/monitor in a cardboard box to block external light, then photograph the m…

It doesn't need to be bulletproof to be very valuable.

However much effort is required to fake it - it's proof that the image is either legit or that much effort went in. There's TONS of cases where it's plausible for someone to have put in the effort to fake a photo with AI (nearly zero effort required) but not remotely plausible that they set up some elaborate high quality photo of a fake.

It's also much more damning if you get caught faking it. Think of the examples where police have been caught posting altered images on social media. The lame excuse that some intern didn't realize it would do more than just upscale the image won't fly if some elaborate setup was required.

Re: Apple Reference Image: A New Approach for Verified Photography

#329

That's a lot of words to say "we re-invented C2PA but made worse by getting our servers involved somehow". Like with C2PA, the entire thing hinges on nobody being able to dump keys or trick the TPM into signing arbitrary image data. The timestamping server is a nice idea (though I don't see why they can't just use a normal timestamping server, I guess to keep control over the protocol) but it doesn't solve the fundam…

> Like with C2PA, the entire thing hinges on nobody being able to dump keys or trick the TPM into signing arbitrary image data.

Is the whole point here that Apple have baked the TPM and keys directly into the sensor. So extracting the keys or injecting arbitrary data, will likely involve the destructive delidding of the image sensor itself.

That’s a significantly higher bar you need to jump, than any approach where the sensor and TPM are separate modules with no cryptographic capabilities in the sensor itself.

From the article > The creation of a secure digital negative begins with a secure boot of the camera sensor into a specialized reference capture mode. The mode instructs the sensor to cryptographically sign pixel data immediately after capture, and prevents the sensor firmware from modifying the data.

Re: Apple Reference Image: A New Approach for Verified Photography

#330

This is really clever from Apple. The journalist use case is just the PR story. This will be really useful for identity verification and insurance apps, and has the potential to shift from "you need a smartphone to be able to live normally" to "you need an iPhone to be able to live normally". There are already plenty of insurances that require you to submit claims through a smartphone app that tries to essentially do…

And it also makes Apple's Private Compute to process all the pictures taken by all the iphones. Can we trust their privacy preservation against a court order?
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