Signs that can reveal a fake photo (2017) • Hacker News Board

Re: Signs that can reveal a fake photo (2017)

#11

Post by hwers » Mon, Sep 06, 2021, 12:58 PM UTC

Cthulhu_ wrote: post #7

hk-im-ad wrote: post #6

With GANs, any fake image detection technique you could derive based on visual data could probably be learned by the discriminator given the right architecture choice.

It's an interesting rat race to see; you could make a fake image using AI, then a fake image detector software, then connect the two until the AI generates images no longer recognizable as fake.

Just a comment: This usually isn't how GAN progress is made. I haven't really seen any GAN that incorporates advances in 'fake detection' directly into its discriminator. Usually it's just GANs getting more data and using smarter math and 'fake predictors' following the development by some 6-12 months.

Re: Signs that can reveal a fake photo (2017)

#12

Post by hk-im-ad » Mon, Sep 06, 2021, 1:21 PM UTC

Cthulhu_ wrote: post #7

hk-im-ad wrote: post #6

With GANs, any fake image detection technique you could derive based on visual data could probably be learned by the discriminator given the right architecture choice.

It's an interesting rat race to see; you could make a fake image using AI, then a fake image detector software, then connect the two until the AI generates images no longer recognizable as fake.

This is how a GAN works. There is a generator and a discriminator. The generator tries to fool the discriminator, and the discriminator tries to detect images generated by the generator. As one gets better, so does the other, until progress converges.

Re: Signs that can reveal a fake photo (2017)

#13

Post by MauranKilom » Mon, Sep 06, 2021, 1:34 PM UTC

JacKTrocinskI wrote: post #10

Pretty sure Benford's law applies to images and can be used as a tool to detect fakes.

Interesting idea, but it's not obvious to me in what way you would apply it.

For example, compositing two images that somehow obey Benford's law should result in something that also obeys it.

Maybe you mean "Benford's law" as in "just general stastical properties", but I hope you had something more specific in mind.

Re: Signs that can reveal a fake photo (2017)

#14

Post by hdm41bc » Mon, Sep 06, 2021, 1:44 PM UTC

Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.

Re: Signs that can reveal a fake photo (2017)

#15

Post by kkielhofner » Mon, Sep 06, 2021, 1:53 PM UTC

It's been really interesting to see another recent uptick in media (and HN) coverage of deepfakes, modified media, etc lately.

There are virtually endless ways to generate ("deepfake") or otherwise modify media. I'm convinced that we're (at most) a couple advancements of software and hardware away from anyone being able to generate or otherwise modify media to the point where it's undetectable (certainly by average media consumers).

This comes up so often on HN I'm beginning to feel like a shill but about six months ago I started working on a cryptographic approach to 100% secure media authentication, verification, and provenance with my latest startup Tovera[0].

With traditional approaches (SHA256 checksums) and the addition of blockchain (for truly immutable and third party verification) we have an approach[1] that I'm confident can solve this issue.

[0] https://tovera.com

[1] https://www.tovera.com/tech

Re: Signs that can reveal a fake photo (2017)

#16

Post by kc0bfv » Mon, Sep 06, 2021, 1:56 PM UTC

hdm41bc wrote: post #14

Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.

In this scenario, it would almost certainly have to be that manufacturers would have to build cameras that cryptographically sign the images and videos. The cameras would have to be able to have that ability, install of the manufacturers doing the signing.

And then what would the Blockchain provide in this case? A chain of cryptographically signed certificates back to a manufacturer is basically the same system we use on the web today TLS certs. No Blockchain required.

And a major problem with that system is making sure the camera only signs genuine images. A nation state actor, or even a large political operation, is going to have an incentive to bypass the protections on that camera - perhaps just driving what the CCD is telling the rest of the camera - so they can produce signed fakes.

That's if they can't just get the private key off the camera, perhaps through a side channel attack - which can be pretty tough to pull off but is very tough to really defend against. Get a private key, game is over for the fraudster.

Re: Signs that can reveal a fake photo (2017)

#17

Post by amelius » Mon, Sep 06, 2021, 2:01 PM UTC

hdm41bc wrote: post #14

Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.

This might lead into a direction we don't want to go. E.g. camera manufacturers can add DRM so you can't copy photos and movies, fingerprinting for CSAM, etc.

Just give me the raw image sensor.

Re: Signs that can reveal a fake photo (2017)

#18

Post by tsimionescu » Mon, Sep 06, 2021, 2:01 PM UTC

kkielhofner wrote: post #15

It's been really interesting to see another recent uptick in media (and HN) coverage of deepfakes, modified media, etc lately. There are virtually endless ways to generate ("deepfake") or otherwise modify media. I'm convinced that we're (at most) a couple advancements of software and hardware away from anyone being able to generate or otherwise modify media to the point where it's undetectable (certainly by average m…

Block chain can at best give you chain-of-custody, but it can't help with the real problem - the original source. Trusting the original source requires, well, trust, so a block chain really adds very little to the solution.

Re: Signs that can reveal a fake photo (2017)

#19

Post by tsimionescu » Mon, Sep 06, 2021, 2:03 PM UTC

hdm41bc wrote: post #14

Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.

Wouldn't filming a good quality screen with a higher refresh rate than the camera FPS defeat this method entirely? Especially so if the desired result is not itself high-def.

Re: Signs that can reveal a fake photo (2017)

#20

Post by kkielhofner » Mon, Sep 06, 2021, 2:08 PM UTC

tsimionescu wrote: post #18

kkielhofner wrote: post #15

It's been really interesting to see another recent uptick in media (and HN) coverage of deepfakes, modified media, etc lately. There are virtually endless ways to generate ("deepfake") or otherwise modify media. I'm convinced that we're (at most) a couple advancements of software and hardware away from anyone being able to generate or otherwise modify media to the point where it's undetectable (certainly by average m…

Block chain can at best give you chain-of-custody, but it can't help with the real problem - the original source. Trusting the original source requires, well, trust, so a block chain really adds very little to the solution.

In our implementation the source/creator of the media is verified as well. I think of our approach as "Twitter blue checkmark meets certificates" (sort of). Of course a user can always take media and re-upload it via any number of ways but they can't do so as any other user. One of our next steps is to have identity verification by way of social media accounts and Stripe identity or another identity verification platform.

The primary verification source is our API that interacts with a traditional data store. Blockchain only serves to add additional verification that we (or anyone else) isn't modifying or otherwise tampering with our verification record.