Re: confirming it's a person

["Stefan Wagner" <ffm.stefan () googlemail com>]

>  I think we have already discussed this topic, and someone said we could
>  use pictures of cats and other animals and ask the user to count the
>  number of cats on the photos.
>
>  Microsoft is working on this, it looks promising.
>
>  http://research.microsoft.com/asirra/

I think a weak point may be that petfinder.com pictures are available
to the public too.

An Attacker could let some bots crawl petfinder.com by Category, grab
the thumbnails
(or the big pictures) and resize 'em to asirra thumbnail size (to
avoid the bottom text "petfinder.com"
Logo on asirra big pictures) and put some CRC of that into a DB (maybe
even make it b/w and
low-res, only take specified part(s) of the picture for the CRC and so
on). This sure won't be perfect, but
for some usable percentage i think it may currently work.

Regards,
 Stefan
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