Ucenter의 역암호화 함수 authcode 함수 코드

 
  
function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) { 
  
 
  
$ckey_length = 4; //           0-32; 
  
//       ，          ，            ，          ，      。 
  
//     ，        ，     = 16   $ckey_length    
  
//      0  ，         
  
 
  
$key = md5($key ? $key : UC_KEY); 
  
$keya = md5(substr($key, 0, 16)); 
  
$keyb = md5(substr($key, 16, 16)); 
  
$keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : ''; 
  
 
  
$cryptkey = $keya.md5($keya.$keyc); 
  
$key_length = strlen($cryptkey); 
  
 
  
$string = $operation == 'DECODE' ? base64_decode(substr($string, $ckey_length)) : sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string; 
  
$string_length = strlen($string); 
  
 
  
$result = ''; 
  
$box = range(0, 255); 
  
 
  
$rndkey = array(); 
  
for($i = 0; $i <= 255; $i++) { 
  
$rndkey[$i] = ord($cryptkey[$i % $key_length]); 
  
} 
  
 
  
for($j = $i = 0; $i < 256; $i++) { 
  
$j = ($j + $box[$i] + $rndkey[$i]) % 256; 
  
$tmp = $box[$i]; 
  
$box[$i] = $box[$j]; 
  
$box[$j] = $tmp; 
  
} 
  
 
  
for($a = $j = $i = 0; $i < $string_length; $i++) { 
  
$a = ($a + 1) % 256; 
  
$j = ($j + $box[$a]) % 256; 
  
$tmp = $box[$a]; 
  
$box[$a] = $box[$j]; 
  
$box[$j] = $tmp; 
  
$result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256])); 
  
} 
  
 
  
if($operation == 'DECODE') { 
  
if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) { 
  
return substr($result, 26); 
  
} else { 
  
return ''; 
  
} 
  
} else { 
  
return $keyc.str_replace('=', '', base64_encode($result)); 
  
} 
  
} 
  
/***************************************************************************/ 
  
$string = authcode("Hello","ENCODE","HTML_TCCJ_AUTH"); 
  
echo $string,'
'; 
  
echo authcode($string,"DECODE","HTML_TCCJ_AUTH"),'
';