Linearized computations - was OCR
Riad S. Wahby
rsw at mit.edu
Sun Aug 12 09:20:38 PDT 2001
Declan McCullagh <declan at well.com> wrote:
> I had thoughts along a similar line as Peter's, except to use numbers.
> Include with <img> tags some .GIFs and ask the person/bot to type in
> the numbers in the GIFs. Generate the filenames randomly and expire
> them after five minutes. Should take you 10 minutes to write a
> prototype CGI script in Perl.
This is done somewhere already. I can't quite remember where, but I
suspect that it's in the EBay registration process.
"For security purposes, retype the numbers to the left."
The numbers aren't vertically aligned, have erratic horizontal
spacing, and are presented against a grid-pattern background. I'm not
sure if this actually helps much against standard OCR, although I'm
pretty sure that the SVMs I work with could be easily trained to
translate the GIFs to text.
--
Riad Wahby
rsw at mit.edu
MIT VI-2/A 2002
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