
Signs that can reveal a fake photo - hvo
http://www.bbc.com/future/story/20170629-the-hidden-signs-that-can-reveal-if-a-photo-is-fake
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Karunamon
There's a YouTuber by the name of Captain Disillusion that has a series of
debunking fake videos, using many of the same techniques described here.

Where it really gets cool is that he does video work for a living, and in many
cases can _even tell you what special effects and stock images from the
software library were specifically used_.

It's great stuff. Example:
[https://www.youtube.com/watch?v=rsXQInxxzBU](https://www.youtube.com/watch?v=rsXQInxxzBU)

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qrbLPHiKpiux
This is eye opening to see the tricks used all in getting you to give someone
your money.

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TazeTSchnitzel
Regarding JPEG compression, there used to be a site that would make a heatmap
of JPEG-induced noise for a given image, so you could see hotspots where it
looked like it had been compressed twice (i.e. manipulated).

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joshu
ELA? Error Level Analysis?

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joecool1029
>ELA? Error Level Analysis?

Yeah, that was it. They shut it down but still have an info page on it:
[http://www.errorlevelanalysis.com/](http://www.errorlevelanalysis.com/)

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eli
It's easy to spoof if you try though, so it only works to detect
unsophisticated forgeries.

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contingencies
Great to read _the government or other criminal groups_ in a BBC article!

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jameslk
It would be interesting if digital cameras would cryptographically sign
photos. I'm sure there would be ways around that too (see also DRM arms race).
Or at the very least use the photographer's private key to sign the photo.
That might not prevent photo manipulation if the photographer wants to
manipulate their photo but would prevent others from manipulating it.

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ams6110
Experts can still spot these clues -- for now. How much longer before better
tools can create altered images/videos that correct for all these defects?
Aligning shadows/reflections seems like something that software should be able
to do.

I think that within the decade, photo/video "evidence" will be something that
can be legitimately questioned unless there's some kind of cryptographic proof
that it hasn't been altered. Cameras will need to "sign" their images,
perhaps?

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acomjean
Canon (probably others) have "verification kits" for using digital photography
as evidence. This is to verify images haven't been tweaked after the fact. Not
sure exactly how it works, but canon at least seems to require the high end 1
series cameras, presumably signing the images..

from the press release: "The kit consists of a dedicated SM (secure mobile)
card reader/writer and verification software. When the appropriate function
(Personal Function 31) on the EOS-1D Mark II or EOS-1Ds is activated, a code
based on the image contents is generated and appended to the image. When the
image is viewed, the data verification software determines the code for the
image and compares it with the attached code. If the image contents have been
manipulated in any way, the codes will not match and the image cannot be
verified as the original."

[https://www.dpreview.com/articles/3146736527/canondvke2](https://www.dpreview.com/articles/3146736527/canondvke2)

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weavie
Surely an easy work around would be to take the picture, doctor it, print it
out, point the camera at the print out and snap.

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zzo38computer
Not sufficient; you will also need to worry about timestamps.

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pvaldes
And with the printer resolution matching the camera

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pcunite
Check out Real-time Face Capture and Reenactment:

[https://youtu.be/ohmajJTcpNk](https://youtu.be/ohmajJTcpNk)

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johansch
This is surprisingly good stuff (for being a bbc.com article - they tend to be
overly light on details).

