Hi,

I'm using PHP 4.4.4. I want to block automatic submissions from
spammers on our web site, so I'd like to use some PHP libraries that
generate those image graphics and require the user to type the
characters in the graphics. Do you have any recommendations on things
you have used that are easy to implement and effective?

Thanks for any advice or experiences you've had, - Dave

> Hi,
>
> I'm using PHP 4.4.4. I want to block automatic submissions from
> spammers on our web site, so I'd like to use some PHP libraries that
> generate those image graphics and require the user to type the
> characters in the graphics. Do you have any recommendations on things
> you have used that are easy to implement and effective?
>
> Thanks for any advice or experiences you've had, - Dave

I use gdlib for easy picture manipulation.
Read more here:
http://dk2.php.net/manual/en/ref.image.php

Looks like gdlib is a part of php from v4.3

..oO(laredotornado@zipmail.com)

>I'm using PHP 4.4.4. I want to block automatic submissions from
>spammers on our web site, so I'd like to use some PHP libraries that
>generate those image graphics and require the user to type the
>characters in the graphics.

That's called a CAPTCHA, in this case a graphical one.

>Do you have any recommendations on things
>you have used that are easy to implement and effective?

No, and I won't use them. There are various accessibility problems with
these graphical CAPTCHAs:

Inaccessibility of CAPTCHA
http://www.w3.org/TR/turingtest/

This link also discusses some alternatives to the inaccessible graphical
CAPTCHAs.

Additionally many of the available implementations are already broken
and can be read by machines:

Breaking a Visual CAPTCHA
http://www.cs.sfu.ca/~mori/research/gimpy/

PWNtcha - captcha decoder
http://sam.zoy.org/pwntcha/

aiCaptcha - Using AI to beat CAPTCHA and post comment spam
http://www.brains-n-brawn.com/defaul...vDir=aicaptcha

XRumer (CAPTCHA breaking spam poster)
http://pandalabs.pandasecurity.com/archive/XRumer.aspx

Micha

laredotornado@zipmail.com wrote:
> Hi,
>
> I'm using PHP 4.4.4. I want to block automatic submissions from
> spammers on our web site, so I'd like to use some PHP libraries that
> generate those image graphics and require the user to type the
> characters in the graphics. Do you have any recommendations on things
> you have used that are easy to implement and effective?
>
> Thanks for any advice or experiences you've had, - Dave
>

Google will find some libraries for you. And it will as not all
spammers have the full set of tools.

You might consider two other options:

1) Ask a random question (you may want a lot of questions) such as 'How
many legs does a dog have?'. This is still accessible, easy for humans,
not so easy for bonehead spammers who only care about captcha graphics.

2) One place uses a wall of small thumbnails with pictures of puppies
and kittens. User has to say which ones are the kittens (maybe 3 out
36 images are kittens). I don't recall the site, but it would be easy
to implement.

On Oct 18, 11:21 pm, Preventer of Work <not_t...@nospam.xxx> wrote:
> laredotorn...@zipmail.com wrote:
> > Hi,
>
> > I'm using PHP 4.4.4. I want to block automatic submissions from
> > spammers on our web site, so I'd like to use some PHP libraries that
> > generate those image graphics and require the user to type the
> > characters in the graphics. Do you have any recommendations on things
> > you have used that are easy to implement and effective?
>
> > Thanks for any advice or experiences you've had, - Dave
>
> Google will find some libraries for you. And it will as not all
> spammers have the full set of tools.
>
> You might consider two other options:
>
> 1) Ask a random question (you may want a lot of questions) such as 'How
> many legs does a dog have?'. This is still accessible, easy for humans,
> not so easy for bonehead spammers who only care about captcha graphics.
>
> 2) One place uses a wall of small thumbnails with pictures of puppies
> and kittens. User has to say which ones are the kittens (maybe 3 out
> 36 images are kittens). I don't recall the site, but it would be easy
> to implement.

Hey Preventer of Work, The idea of the question is a really good one.
Do you come up with your own list of questions or is there a pre-
written list out there?

Thanks for the suggestion, - Dave

On Thu, 18 Oct 2007 12:31:41 -0700, "laredotornado@zipmail.com"
<laredotornado@zipmail.com> wrote:

>Thanks for any advice or experiences you've had, - Dave

Cheat and use this:
<http://recaptcha.net/>
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