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Attested Audio with ZKP

ddkang.github.io

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Re: Attested Audio with ZKP

#11

Post by ssfrr »

> In our setting, we can compute a function that computes the hashes of the inputs and outputs the edited audio from the inputs. By revealing the hashes, we can be assured that the inputs match the recorded audio!

I don't understand how this works, or what exactly is being proven here. For instance, you could silence the given inputs and inject some other unrelated audio, so the fact that your output hash incorporates the input hashes doesn't seem very meaningful.

I figure I must be missing something here.

Re: Attested Audio with ZKP

#12

Post by ssfrr »

kobalsky wrote: post #9
Adrox wrote: post #8

I don't understand how this avoids any simple attack both for audio or video: - Alter/manipulate the audio/video has much as you want. - Play it. - Have a "attested" microphone/video recording the "manipulated audio/video". For video maybe you can actually try to prove that's recording a screen not the real event, but seems much harder for audio, you can just say the echos/ distortions came from the environment...

I think in this case the point would be to trust the source publishing the audio and not content. I cam see a gpg like registry where news stations publish their public keys to verify that their audio / video snippets have not been tampered with.

Yeah, this is my understanding also. I don't understand how this is better than the publisher signing the content with their own key though, rather than relying on a special microphone.

I wish the article was more clear on what threat model they're trying to address.

Re: Attested Audio with ZKP

#13

Post by kj4ips »

didntcheck wrote: post #6
lionkor wrote: post #2

> The hardware manufacturer can destroy the private key after it is placed on the device. By doing so, the private key is inaccessible! I'm pretty sure the private key is very accessible, if it's used at runtime which it is. Just not easily.

Yeah. People have been hoping for a signed "Photoshop-proof camera" since digital image manipulation was invented, but it has the same limitations as any form of DRM. It only slows people down a bit. There's also the analog hole - i.e. just stick your "attested" microphone in front of a speaker

Canon tried to do this with their ODD system, and they got kinda close, but it is possible to extract the key from a given camera, and forge signatures.

Their verification system also seems to include a smartcard or SD card-like thing (which might be doing something special, or might just be DRM)

Re: Attested Audio with ZKP

#14

Post by flangola7 »

lionkor wrote: post #2

> The hardware manufacturer can destroy the private key after it is placed on the device. By doing so, the private key is inaccessible! I'm pretty sure the private key is very accessible, if it's used at runtime which it is. Just not easily.

Extracting the private key out of a modern HSM enclave is essentially impossible for anything less than NSA-level capabilities.

Re: Attested Audio with ZKP

#15

Post by flangola7 »

lionkor wrote: post #7
didntcheck wrote: post #6

Earlier quoted context omitted.

Yeah. People have been hoping for a signed "Photoshop-proof camera" since digital image manipulation was invented, but it has the same limitations as any form of DRM. It only slows people down a bit. There's also the analog hole - i.e. just stick your "attested" microphone in front of a speaker

or rip out the wires and attach whatever speaker you want, not really detectable

It is detectable if the other components are cryptographically paired, like they are in newer iPhones.

Go try to swap a camera or screen between two identical iPhone models, it won't work.

Re: Attested Audio with ZKP

#16

Post by vagab0nd »

ssfrr wrote: post #11

> In our setting, we can compute a function that computes the hashes of the inputs and outputs the edited audio from the inputs. By revealing the hashes, we can be assured that the inputs match the recorded audio! I don't understand how this works, or what exactly is being proven here. For instance, you could silence the given inputs and inject some other unrelated audio, so the fact that your output hash incorporate…

The editing can be checked. Basically the verifier is given the input hash, the editing function (e.g. remove noise) and the output. By using zk-snark the verifier can be convinced that yes indeed the output is the result of editing the input, and the input hash is the result of hashing the input.
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