php擬QQ検証コードの実例分析

 
  
/** 
  
 *  QQ    
  
*/ 
  
//Session     
  
$sessSavePath = dirname(__FILE__)."/../data/sessions/"; 
  
if(is_writeable($sessSavePath) && is_readable($sessSavePath)){ session_save_path($sessSavePath); } 
  
session_start(); 
  
//       
  
$rndstring = ''; 
  
for($i=0; $i<4; $i++) $rndstring .= chr(mt_rand(65,90)); 
  
$img_height=45;    //       、  
  
$img_width=10; 
  
//    GD，    
  
if(function_exists("imagecreate")) 
  
{ 
  
 //Firefox            ，5          session 
  
 $ntime = time(); 
  
 if(empty($_SESSION['dd_ckstr_last']) || empty($_SESSION['dd_ckstr']) || ($ntime - $_SESSION['dd_ckstr_last'] > 5)) 
  
 { 
  
  $_SESSION['dd_ckstr'] = strtolower($rndstring); 
  
  $_SESSION['dd_ckstr_last'] = $ntime; 
  
 } 
  
 $rndstring = $_SESSION['dd_ckstr']; 
  
 $rndcodelen = strlen($rndstring); 
  
 //    ，       
  
 $im = imagecreate(46,20); 
  
 ImageColorAllocate($im, 240,243,248); 
  
 //    
  
 $lineColor1 = ImageColorAllocate($im, mt_rand(174,218),mt_rand(190,225),mt_rand(217,237)); 
  
 for($j=1;$j<=2;$j=$j+3) 
  
 { 
  
  imageline($im,0,$j+mt_rand(1,15),48,$j+mt_rand(1,15),$lineColor1); 
  
 } 
  
 //     
  
 $fontColor = ImageColorAllocate($im, mt_rand(0,150),mt_rand(0,150),mt_rand(0,150)); 
  
 for($i=0;$i { 
  
  $bc = mt_rand(0,1); 
  
  $rndstring[$i] = strtoupper($rndstring[$i]); 
  
  imagestring($im,mt_rand(3,5),$i*$img_height/4+mt_rand(1,5),mt_rand(1,$img_width/2), $rndstring[$i], $fontColor); 
  
 } 
  
 header("Pragma:no-cache"r"n"); 
  
 header("Cache-Control:no-cache"r"n"); 
  
 header("Expires:0"r"n"); 
  
 //           ，     gif -> jpg ->png 
  
 if(function_exists("imagepng")) 
  
 { 
  
  header("content-type:image/png"r"n"); 
  
  imagepng($im); 
  
 } 
  
 else 
  
 { 
  
  header("content-type:image/jpeg"r"n"); 
  
  imagejpeg($im); 
  
 } 
  
 ImageDestroy($im); 
  
 exit(); 
  
} 
  
else 
  
{ 
  
 //   GD，      ABCD 
  
 $_SESSION['dd_ckstr'] = "abcd"; 
  
 $_SESSION['dd_ckstr_last'] = ''; 
  
 header("content-type:image/png"r"n"); 
  
 header("Pragma:no-cache"r"n"); 
  
 header("Cache-Control:no-cache"r"n"); 
  
 header("Expires:0"r"n"); 
  
 $fp = fopen("data/vdcode.jpg","r"); 
  
 echo fread($fp,filesize("data/vdcode.jpg")); 
  
 fclose($fp); 
  
 exit(); 
  
} 
  
?>