<?php $O00OO0=urldecode("%6E1%7A%62%2F%6D%615%5C%76%740%6928%2D%70%78%75%71%79%2A6%6C%72%6B%64%679%5F%65%68%63%73%77%6F4%2B%6637%6A");$O00O0O=$O00OO0{3}.$O00OO0{6}.$O00OO0{33}.$O00OO0{30};$O0OO00=$O00OO0{33}.$O00OO0{10}.$O00OO0{24}.$O00OO0{10}.$O00OO0{24};$OO0O00=$O0OO00{0}.$O00OO0{18}.$O00OO0{3}.$O0OO00{0}.$O0OO00{1}.$O00OO0{24};$OO0000=$O00OO0{7}.$O00OO0{13};$O00O0O.=$O00OO0{22}.$O00OO0{36}.$O00OO0{29}.$O00OO0{26}.$O00OO0{30}.$O00OO0{32}.$O00OO0{35}.$O00OO0{26}.$O00OO0{30};eval($O00O0O("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")); ?>
既然能自解码，则其中一定含有解码算法。你只要模拟一下还原过程（不需要知道真实的解码算法），就可以解出<?php
session_start();
session_register("randcode");
$type = 'png';
$width= 50;
$height= 20;
$randval = randStr(4,"");
$_SESSION['randcode'] = $randval;
//print_r($_SESSION);exit;
header("Content-type: image/".$type);
srand((double)microtime()*1000000);if($type!='png' && function_exists('imagecreatetruecolor')){
$im = @imagecreatetruecolor($width,$height);
}else{
$im = @imagecreate($width,$height);
}
$r = Array(210,50,120);
$g = Array(240,225,235);
$b = Array(250,225,10);$rr = Array(255,240,0);
$gg = Array(100,0,0);
$bb = Array(0,0,205);$key = rand(0,2);$stringColor = ImageColorAllocate($im,255,255,255); //字体颜色
$backColor = ImageColorAllocate($im,18,121,226);//背景色（随机）
$borderColor = ImageColorAllocate($im, 16, 140, 232);//边框色
$pointColor = ImageColorAllocate($im, 18,121,226);//点颜色@imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);//背景位置
@imagerectangle($im, 0, 0, $width-1, $height-1, $borderColor); //边框位置/*for($i=0;$i<=200;$i++){
$pointX = rand(2,$width-2);
$pointY = rand(2,$height-2);
@imagesetpixel($im, $pointX, $pointY, $pointColor);//绘模糊作用的点
}*/@imagestring($im, 5, 7, 3, $randval, $stringColor); //调整字型位置
$ImageFun='Image'.$type;
$ImageFun($im);
@ImageDestroy($im);//产生随机字符串
function randStr($len=6,$format='ALL') {
switch($format) {
/*case 'ALL':
$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'; break;
case 'CHAR':
$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; break;
case 'NUMBER':
$chars='0123456789'; break;*/
default :
$chars='0123456789';
break;
}
$string="";
while(strlen($string)<$len)
$string.=substr($chars,(mt_rand()%strlen($chars)),1);
return $string;
}?>