Secure REQ

<?php
/*
 Secure HTTP Request
 ----
  Coded by Kyl3
  (c) 2012
*/
if(isset($_GET["id"]) && isset($_GET["s"]) && isset($_GET["r"])){
function NumberByToken($num) {
if ($num == "c4ca4238a0b923820dcc509a6f75849b")
            {
                return 1;
            }
            else if ($num == "c81e728d9d4c2f636f067f89cc14862c")
            {
                return 2;
            }
            else if ($num == "eccbc87e4b5ce2fe28308fd9f2a7baf3")
            {
                return 3;
            }
            else if ($num == "a87ff679a2f3e71d9181a67b7542122c")
            {
                return 4;
            }
            else if ($num == "e4da3b7fbbce2345d7772b0674a318d5")
            {
                return 5;
            }
            else if ($num == "1679091c5a880faf6fb5e6087eb1b2dc")
            {
                return 6;
            }
            else if ($num == "8f14e45fceea167a5a36dedd4bea2543")
            {
                return 7;
            }
            else if ($num == "c9f0f895fb98ab9159f51fd0297e236d")
            {
                return 8;
            }
            else if ($num == "45c48cce2e2d7fbdea1afc51c7c6ad26")
            {
                return 9;
            }
            else
            {
                return 999;
            }
}
function ParseOp($hash) {
                if ($hash == "3389dae361af79b04c9c8e7057f60cc6")
            {
                return "*";
            }
            else if ($hash == "6666cd76f96956469e7be39d750cc7d9")
            {
                return "/";
            }
            else if ($hash == "d41d8cd98f00b204e9800998ecf8427e")
            {
                return "+";
            }
            else if ($hash == "336d5ebc5436534e61d16e63ddfca327")
            {
                return "-";
            }
            else
            {
                return "";
            }
};
function hex($msg){
   $text = $msg;
   $encoded = PREG_REPLACE (
           "'(.)'e"
         ,"dechex(ord('\\1'))"
         ,$text
   );
return $encoded;
};
function parse($msg){
    $msg = str_ireplace("\n", "", hex(strrev(str_rot13(hex(base64_encode(hex(str_rot13(base64_encode(strrev(hex(base64_encode(str_rot13(hex(base64_encode(strrev(base64_encode(hex(strrev(base64_encode(str_rot13(hex($msg))))))))))))))))))))));
    return $msg;
}
$n1 = NumberByToken($_GET['id']);
$n2 = NumberByToken($_GET['s']);
$op = $_GET['r'];
if(ParseOp($op) == "*"){
 $resp = $n1 * $n2;
} else if(ParseOp($op) == "+"){
 $resp = $n1 + $n2;
} else if(ParseOp($op) == "-"){
 $resp = $n1 - $n2;
};
$ver = "1.0";
$Secure = parse("token: ".$_SERVER['REMOTE_ADDR']."|auth: ".md5($_SERVER['REMOTE_ADDR'])."|result: ".$resp."|build: ".$ver);
echo $Secure;
exit;
}
exit;
?>