Re: Going from simple to super CAPTCHA
| From: | Robert Cummings | Date: | Tue, 12 Jun 2007 19:54:36 +0000 |
| Subject: | Re: Going from simple to super CAPTCHA | ||
| References: | 1 2 3 4 5 6 7 8 9 10 11 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-256764@lists.php.net to get a copy of this message | ||
On Tue, 2007-06-12 at 21:46 +0200, Tijnema wrote:
> On 6/12/07, Robert Cummings <robert@interjinn.com> wrote:
> > On Tue, 2007-06-12 at 15:06 -0400, Daniel Brown wrote:
> > >
> > > Okay, here's something I whipped up today:
> > >
> > > http://pilotpig.com/captcha/index.php
> > >
> > > Works pretty well, but keep in mind that it's in the very early
> > > stages. I randomized the position and size to assist in throwing off
> > > Turing detection, and added color not only to screw with the
> > > color-detection schemes, but also in case it overlays the target
> > > bubble. It's 600x400, so that's 240,000 potential spots to click,
> > > with random size, location, and area coordinates thrown in the mix.
> >
> > Nice, one problem though... the text is unreadable on some backgrounds.
> > I suggest you outline it or something. Easy to do by drawing the font 5
> > times. 4 times for the outline where you offset the drawing location by:
> >
> > (-1, 0), (0,1), (1,0), (0,1)
> >
> > Then change colour and draw the font at the original location.
> >
> > Cheers,
> > Rob.
>
> Yes noticed that problem too, but this seems quite easy to crack, Get
> the text from the image, get the color of the text and search for tha
> tcolor circle.
>
> Tijnema
>
> Btw, I clicked the pixel in the middle, and did 10 refreshes, and I
> had 5 right....
*lol* Yeah, some of the circles are pretty big... not sure he accounted
for the circle in question being completely hidden by other circles.
Cheers,
Rob.
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