discuz 经典php加密解密函数 authcode 解析

宿海仁太

function authcode($string, $operation='DECODE', $key='', $expiry=0)
{
$ckey_length = 4;

$key = md5($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('0d', $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));
}
}

//加密
$data = array('kid'=>333, 'time'=>time());
$authData = authcode(json_encode($data), 'ENCODE');



//解密
print_r(json_decode(authcode("ssssss",'DECODE','abc'), true));

宿海仁太

自己顶一次