
Deepfake-busting apps can spot even a single pixel out of place - mkm416
https://www.technologyreview.com/s/612357/deepfake-busting-apps-can-spot-even-a-single-pixel-out-of-place/
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gus_massa
The title is very misleading. They store some fingerprints of some photos in
their server and then they compare them with the fingerprint of the viral
images. If the viral image is a variant of the image previously submitted they
can spot the difference, even a single pixel difference. (I don't know if the
algorithm is robust enough to survive cropping, brightness correction, and
other modification that are allowed.) (You can get a single pixel difference
detection with MD5, CRC32, sha1, … the difficult part is not overdetection.)

They can't get an unknown image and classify it as real or deepfake.

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gearhart
This appears to be deceptive marketing.

The technology that's being discussed here is just taking a hash of the image
at the point when it's created and using a third party service and standard
cryptography to authenticate it.

You can be sure that the image was taken using a company's app because the
image hash was signed with their key when it was taken, and you can be sure
that it hasn't changed since then because they know that a photo with that
exact signature was once taken with their app.

Now, let's be honest, that's almost certainly the most sensible way to counter
fake imagery - if you want someone to believe a photo is real, prove who took
it and when using the same technology that's used to secure your bank account.

However, the implication in all of these overly-hyped articles about the
products is that it's some kind of "war of the robots" in which they're trying
to train software to spot changes and hollywood-esque "inconsistencies".

That's really unhelpful for two reasons: \- it makes anyone even vaguely
technical deeply distrust anything they say, since it's not a process that
could come out with a reliable product (any ML algorithm like this can be
gamed, and the whole point here is absolute reliability) \- it implies that
this process can be used on any photo and so you could identify that something
was fake if it just appeared on the internet, that's not the case here

Here are the two companies, for reference:
[https://truepic.com](https://truepic.com)
[https://www.serelay.com](https://www.serelay.com)

edit: gus_masa made the same point rather more concisely

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Yaa101
The problem is not debunking deep fakes, I am sure this can be done with
algorythms easy in the long term. The problem of any fakes is that it does not
need that much sophistication to convince the majority of people that have a
lower than average IQ and set them up to do a whitchhunt. This has proven to
work since the time we people roam this earth. The problem is that the big
public can only be convinced of fakery months to years after the hunted has
died or the reputation was killed, and even then a part of the public will
keep on believing false memes and myths. I think we never will able to find a
solution for that as long as we people exsist.

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nathan_long
Proving the legitimacy of a photo or video is a great problem to try to solve
in the age of "fake news" accusations and extremely powerful editing software.

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Arubis
While I agree in principle, I don’t think merely having this technological
capability is sufficient. At this point, unfortunately, accusations of “fake
news” seem to be blindly believed without verification even if facts are
clearly available and easily accessible.

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nathan_long
True. People can always find a reason to justify their belief or disbelief if
they really want to.

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3pt14159
This is really cool, but I have a question. If we go back to using actual film
does this help at all? I can imagine cameras and recorders for things like war
capturing two copies; one digital, one film. If there are unfakeable or hard
to fake artifacts in film one could imagine the recordings could validate each
other. It would also make good insurance against cyber attack from illiberal
governments.

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hsk0823
Film can be "faked". Negatives can be modified. They're all chemical processes
that can be coaxed into producing images that didn't exist when the photo was
taken.

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ajnin
Even if this technology can spot fakes, humans can't, that the whole point and
danger of such lifelike fakes. People are used to react to images in a certain
way, I'm sure a large part of which is hardwired in our brains, we aren't
going to start checking cryptographic signatures for everything we see

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hsk0823
BeyondCorp for life?

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sharemywin
Couldn't you use a GAN to build a more sophisticated generator?

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resters
wouldn't a GAN be able to tune it until it passes the deep fake detection
test?

