[cryptography] CAPTCHA as a Security System?

Peter Gutmann pgut001 at cs.auckland.ac.nz
Tue Jan 3 01:54:40 EST 2012

=?UTF-8?Q?lodewijk_andr=C3=A9_de_la_porte?= <lodewijkadlp at gmail.com> writes:

>Our cozy dutch supermarkets are trying self-checkout systems themselves. They
>sometimes check carts with what's scanned. My dad's theory was that people
>are so afraid to have forgotten that they'd most likely scan their products
>multiple times more often than they forgot, and that relatively little people
>steal anyway.

The way it's done here, the checkout system knows the approximate weight of
each item that you scan, and if you don't add an item of that weight to the
shopping next to the scanner, they complain.  This acts as an auditing system
for the scanning, if you accidentally double-scan or accidentally miss a scan
they'll catch it.


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