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<?php
/**
* CAPTCHA generator script.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.pradosoft.com/
* @copyright Copyright © 2005-2007 PradoSoft
* @license http://www.pradosoft.com/license/
* @version $Id: $
* @package System.Web.UI.WebControls.assets
*/
require_once(dirname(__FILE__).'/captcha_key.php');
$token='error';
if(isset($_GET['options']))
{
$str=base64_decode($_GET['options']);
if(strlen($str)>32)
{
$hash=substr($str,0,32);
$str=substr($str,32);
if(md5($privateKey.$str)===$hash)
{
$options=unserialize($str);
$publicKey=$options['publicKey'];
$tokenLength=$options['tokenLength'];
$caseSensitive=$options['caseSensitive'];
$alphabet=$options['alphabet'];
$token=generateToken($publicKey,$privateKey,$alphabet,$tokenLength,$caseSensitive);
}
}
}
displayToken($token);
function generateToken($publicKey,$privateKey,$alphabet,$tokenLength,$caseSensitive)
{
$token=substr(hash2string(md5($publicKey.$privateKey),$alphabet).hash2string(md5($privateKey.$publicKey),$alphabet),0,$tokenLength);
return $caseSensitive?$token:strtoupper($token);
}
function hash2string($hex,$alphabet='')
{
if(strlen($alphabet)<2)
$alphabet='234578adefhijmnrtABDEFGHJLMNQRT';
$hexLength=strlen($hex);
$base=strlen($alphabet);
$result='';
for($i=0;$i<$hexLength;$i+=6)
{
$number=hexdec(substr($hex,$i,6));
while($number)
{
$result.=$alphabet[$number%$base];
$number=floor($number/$base);
}
}
return $result;
}
function displayToken($token)
{
$length=strlen($token);
$width=45*$length;
$height=70;
$image=imagecreatetruecolor($width,$height);
$font=dirname(__FILE__).DIRECTORY_SEPARATOR.'verase.ttf';
$vred=rand(0,100);
$vgreen=rand(0,100);
$vblue=rand(0,100);
for($x=0;$x<$width;++$x)
{
for($y=0;$y<$height;++$y)
{
$vred+=rand(-2,2);
$vgreen+=rand(-2,2);
$vblue+=rand(-2,2);
if($vred<0) $vred=0; if($vred>150) $vred=75;
if($vgreen<0) $vgreen=0; if($vgreen>150) $vgreen=75;
if($vblue<0) $vblue=0; if($vblue>150) $vblue=75;
$col = imagecolorallocate($image, $vred, $vgreen, $vblue);
imagesetpixel($image, $x, $y, $col);
imagecolordeallocate($image, $col);
}
}
imagefilter($image,IMG_FILTER_GAUSSIAN_BLUR);
for($i=0;$i<$length;$i++)
{
$vred = rand(150, 240);
$vgreen = rand(150, 240);
$vblue = rand(150, 240);
$col = imagecolorallocate($image, $vred, $vgreen, $vblue);
$char = $token[$i];
imagettftext($image, rand(40, 50), rand(-10, 20), 13 + (40 * $i), rand(50, imagesy($image) - 10), $col, $font, $char);
imagecolordeallocate($image, $col);
}
imagefilter($image,IMG_FILTER_GAUSSIAN_BLUR);
imagepng($image);
imagedestroy($image);
}
?>
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