[Cryptography] Facebook -> SteganographyBook

Tom Mitchell mitch at niftyegg.com
Tue Jan 27 18:24:31 EST 2015

On Tue, Jan 27, 2015 at 2:20 PM, grarpamp <grarpamp at gmail.com> wrote:

> On Tue, Jan 27, 2015 at 10:37 AM, Henry Baker <hbaker1 at pipeline.com>
> wrote:
> > Wickr launches encrypted Facebook feature
> > ...
> > The San Francisco-based start-up is using steganography ­ the art of
> covered or hidden writing ­ to create a more private version of the world’s
> largest social network.

Facebook fiddles with images to optimize their storage and display.
They hide or scrub EXIF information as well.  This must be a very
clever trick to pack a payload into an image on FB.

This morning I uploaded four images to FB (yes puppies and flowers). I
recovered one back from FB.  As you can see the most recent is not
like the others and shows the image has been modified and is smaller
even when the original pixel dimensions had been reduced to match a
common screen display resolution (1024 pix wide). -rw-r-----. 1 bob
bob  218214 Jan 27 14:51 /tmp/qq11.jpg -rw-rw-r--. 1 bob bob 1734818
Jan 27 14:25 /var/tmp/Sunny/_2343.jpg -rw-rw-r--. 1 bob bob 1810200
Jan 27 14:26 /var/tmp/Sunny/_2512.jpg -rw-rw-r--. 1 bob bob 1857165
Jan 27 14:26 /var/tmp/Sunny/_2528.jpg -rw-rw-r--. 1 bob bob  897450
Jan 27 14:25 /var/tmp/Sunny/_2295.jpg

  T o m    M i t c h e l l
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