| Author |
Using a CAPTCHA image with PHP
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| Pyromancer 2005-01-13, 11:15 pm |
| I'm using PHP and I would like to implement randomly generated Captcha(
completely automated public Turing test to tell computers and humans apart)
images. For an example, go to Paypal.com registration. They have these
distorted images with letters that they ask you to type in. I''ve searched for
PHP scripts to do this but I could not find anything. How could I implement
this?
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| Kramerica Industries 2005-01-13, 11:15 pm |
| Example here:
http://tinyurl.com/3pg6c
See this presentation:
http://nyphp.org/content/presentations/GDintro/
Specifically
http://nyphp.org/content/presentations/GDintro/gd23.php
"Pyromancer" <webforumsuser@macromedia.com> wrote in message
news:cs77qf$4il$1@forums.macromedia.com...
> I'm using PHP and I would like to implement randomly generated Captcha(
> completely automated public Turing test to tell computers and humans
> apart)
> images. For an example, go to Paypal.com registration. They have these
> distorted images with letters that they ask you to type in. I''ve
> searched for
> PHP scripts to do this but I could not find anything. How could I
> implement
> this?
>
| |
| Pyromancer 2005-01-14, 4:15 am |
| The links that you gave me don't seem to relate to Captcha images at al. The
first picture is just plain text and is not distorted in any way. Are there
any other resources that would teach me how to implement this? It needs to be
distorted and impossible for a robot to read. Just go to Paypal registration
and see there!
| |
| Kramerica Industries 2005-01-14, 4:15 am |
| Have you tried http://www.captcha.net/ ?
Not being a robot expert ... Can a robot really read text within an image,
if so how?
"Pyromancer" <webforumsuser@macromedia.com> wrote in message
news:cs7fv3$bk1$1@forums.macromedia.com...
> The links that you gave me don't seem to relate to Captcha images at al.
> The
> first picture is just plain text and is not distorted in any way. Are
> there
> any other resources that would teach me how to implement this? It needs to
> be
> distorted and impossible for a robot to read. Just go to Paypal
> registration
> and see there!
>
| |
| Joe Makowiec 2005-01-14, 4:15 am |
| On 13 Jan 2005 in macromedia.dreamweaver, Kramerica Industries wrote:
> Have you tried http://www.captcha.net/ ?
>
> Not being a robot expert ... Can a robot really read text within an
> image, if so how?
Dan Vendel started a thread a month or so back - he pointed out that if
you googled a certain phrase, you'd come to his website. The phrase
occured only in an image in fairly tiny type, and, as far as I am aware,
nowhere else. I don't remember offhand what it was, but the
demonstration was pretty convincing that GoogleBot was picking up text
from images.
--
Joe Makowiec
http://makowiec.net/
Email: http://makowiec.net/email.php
| |
|
| bot 'sees' an image.
evaluates image for contrast patterns that would be more likely to be text
vs. photo content.
rough fit contrast pattern against series of common font patterns, to
discern if there are letter patterns.
if there are letter patterns, use fuzzy logic to fit series of letters to a
dictionary list of words
the end result, a bot that can "read" bitmap text from an image file.
> Not being a robot expert ... Can a robot really read text within an image,
> if so how?
| |
| Pyromancer 2005-01-14, 4:15 am |
| Yes, I have a tried captcha.net, but there are just announcements and
demonstrations there - nothing i can use. Isn't there any PHP script that can
generate those distorted images? How do the sites that implement Captcha's do
it? Thanks
| |
|
| sorry, i missed the start of the thread.
you are looking to put a confirmation image into your form to cut down on
bot submissions?
some info here maybe:
http://www.junkeater.com/index.php
could probably turn up some tutorials on doing it yourself, using the GD
image library with php.
> Isn't there any PHP script that can
> generate those distorted images?
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| Michael Fesser 2005-01-14, 7:14 am |
| .oO(Joe Makowiec)
>I don't remember offhand what it was, but the
>demonstration was pretty convincing that GoogleBot was picking up text
>from images.
http://catalogs.google.com/
Micha
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| Kramerica Industries 2005-01-14, 12:15 pm |
| >> Dan Vendel started a thread a month or so back
Just Googled that thread. Pretty neat.
What's to say down the road they wont have the tech to parse these CAPTCHA
images?
"Joe Makowiec" <makowiec@invalid.invalid> wrote in message
news:Xns95DDEEED7497makowiecatnycapdotrE@216.104.212.96...
> On 13 Jan 2005 in macromedia.dreamweaver, Kramerica Industries wrote:
>
>
> Dan Vendel started a thread a month or so back - he pointed out that if
> you googled a certain phrase, you'd come to his website. The phrase
> occured only in an image in fairly tiny type, and, as far as I am aware,
> nowhere else. I don't remember offhand what it was, but the
> demonstration was pretty convincing that GoogleBot was picking up text
> from images.
>
> --
> Joe Makowiec
> http://makowiec.net/
> Email: http://makowiec.net/email.php
| |
| darrel 2005-01-14, 12:16 pm |
| > Yes, I have a tried captcha.net, but there are just announcements and
> demonstrations there - nothing i can use. Isn't there any PHP script that
can
> generate those distorted images?
Google seems to find some:
http://www.google.com/search?q=php+captcha
| |
| darrel 2005-01-14, 12:16 pm |
| > What's to say down the road they wont have the tech to parse these CAPTCHA
> images?
See the link in my other reply. We already have this. ;o)
-Darrel
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| darrel 2005-01-14, 12:16 pm |
| > Spammers, porn and accessibility
What a great article title. ;o)
-Darrel
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| darrel 2005-01-14, 12:16 pm |
| > Not being a robot expert ... Can a robot really read text within an image,
> if so how?
OCR technology has been around for well over a decade.
In fact, it's not impossible for programs to read distorted text either:
http://www.cs.berkeley.edu/%7Emori/gimpy/gimpy.html
Personally, though I haven't seen it used yet, I think it's better to simply
use plain-text logic puzzles:
write the following number in numeral form: one thousand
enter the letter that falls between c and e
enter this word but using all capital letters: cat
etc.
The advantage is that you can leave them plain-text, making them more
accessible to those that don't see images. The disadvantage is that you may
exclude folks that have cognitive disabilities.
-Darrel
| |
| Kramerica Industries 2005-01-14, 7:16 pm |
| >>OCR technology has been around for well over a decade.
I knew that & thanks, but I was looking for the technical answer, which Alan
gave above.
"darrel" <notreal@hotmail.com> wrote in message
news:cs8otp$ph7$1@forums.macromedia.com...
>
> OCR technology has been around for well over a decade.
>
> In fact, it's not impossible for programs to read distorted text either:
>
> http://www.cs.berkeley.edu/%7Emori/gimpy/gimpy.html
>
>
> Personally, though I haven't seen it used yet, I think it's better to
> simply
> use plain-text logic puzzles:
>
> write the following number in numeral form: one thousand
> enter the letter that falls between c and e
> enter this word but using all capital letters: cat
>
> etc.
>
> The advantage is that you can leave them plain-text, making them more
> accessible to those that don't see images. The disadvantage is that you
> may
> exclude folks that have cognitive disabilities.
>
> -Darrel
>
>
| |
|
| bot 'sees' an image.
evaluates image for contrast patterns that would be more likely to be text
vs. photo content.
rough fit contrast pattern against series of common font patterns, to
discern if there are letter patterns.
if there are letter patterns, use fuzzy logic to fit series of letters to a
dictionary list of words
the end result, a bot that can "read" bitmap text from an image file.
> Not being a robot expert ... Can a robot really read text within an image,
> if so how?
| |
| Joe Makowiec 2005-01-19, 4:18 am |
| On 13 Jan 2005 in macromedia.dreamweaver, Kramerica Industries wrote:
> Have you tried http://www.captcha.net/ ?
>
> Not being a robot expert ... Can a robot really read text within an
> image, if so how?
Dan Vendel started a thread a month or so back - he pointed out that if
you googled a certain phrase, you'd come to his website. The phrase
occured only in an image in fairly tiny type, and, as far as I am aware,
nowhere else. I don't remember offhand what it was, but the
demonstration was pretty convincing that GoogleBot was picking up text
from images.
--
Joe Makowiec
http://makowiec.net/
Email: http://makowiec.net/email.php
| |
| Pyromancer 2005-01-19, 4:18 am |
| Yes, I have a tried captcha.net, but there are just announcements and
demonstrations there - nothing i can use. Isn't there any PHP script that can
generate those distorted images? How do the sites that implement Captcha's do
it? Thanks
| |
|
|
| darrel 2005-01-19, 4:18 am |
| > Yes, I have a tried captcha.net, but there are just announcements and
> demonstrations there - nothing i can use. Isn't there any PHP script that
can
> generate those distorted images?
Google seems to find some:
http://www.google.com/search?q=php+captcha
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