<?
function captcha_check($action)
{
   ///////////////////// Change these settings /////////////////////
   // The fonts to use. Change to any fonts you like, you can even
   // add as many as you like.
   $fonts = array("baveuse3.ttf","international.ttf","no_problem.ttf");

   // Background images to write text on. Make sure they are JPG files!
   // The pictures should be 160x50 in size.
   $pictures = array("1.jpg","2.jpg");

   // Set this to a secret word only you know about. Letters and numbers
   // are both OK!
   $secretword = "set this to a secret word only you know about";

   ////////////////// No more changes are needed ///////////////////
   $txt = substr(md5($_SERVER[REMOTE_ADDR] ." ". date('d') ." ". date('m') ." ". date('h') ." ". $secretword),3,5);

   if ($action == "img")
   {
      Header("Content-type: image/jpg");

      $numpic = rand(0,(count($pictures)-1));
      $im = imagecreatefromjpeg($pictures[$numpic]);

      $white = ImageColorAllocate($im, 255, 255, 255);
      $black = ImageColorAllocate($im, 0, 0, 0);
      $i = 0;
      while ($i < 5)
      {
         $angle = 15 - rand(0,40);
         $fnum = rand(0,(count($fonts)-1));
         $font = $fonts[$fnum];
         $fontsize = 25;
      
         ImageTTFText($im,$fontsize,$angle,($i * 30 + 5),36,$black,$font,substr($txt,$i,1));
         $i++;
      }

      Imagejpeg($im);
      ImageDestroy($im);
   }
   else
   {
      if ($txt == $action)
      {
         return 1;
      }
      else
      {
         return 0;
      }
   }
};
?>

<?
include("functions.php");
captcha_check("img");
?>

<IMG SRC="image.php" BORDER=0 ALT="Fill in the numbers and letters you see in this picture in the field below" /><BR />

<?
include("functions.php");
if ($_POST['do'] == "check")
{
   // Do the check if the user entered the same numbers/letters as the picture.
   if (captcha_check($_POST['letters']))
   {
      // The user wrote correct combination of letters and numbers
      echo '<P><STRONG><FONT COLOR=green>You entered the correct text!</FONT></STRONG></P>';
   }
   else
   {
      //Sorry, please try again.
      echo '<P><FONT COLOR=red>Sorry, wrong text! Try again.</FONT></P>';
   }
}
?>
<FORM METHOD=post ACTION="<? echo $_SERVER[PHP_SELF]; ?>">
<INPUT TYPE=hidden NAME=do VALUE=check>
<IMG SRC="image.php" BORDER=0 ALT="Fill in the numbers and letters you see in this picture in the field below" /><BR />
<B>Fill in the numbers and letters you see on the picture above:</B><BR>
<INPUT TYPE=text NAME=letters SIZE=5><INPUT TYPE=submit VALUE="Submit!">
</FORM>