Encrypted and Decrypted { Caesar }

<?php
/*
 Author   : Lov3rDns
 Title    : Encrypted and Decrypted { Caesar }
 tw/video : https://twitter.com/NetDevr/status/748706162405552129
 thanks @r00t3rz for the effort : http://www.exploit4arab.org/exploits/1382
*/
set_time_limit(0);
error_reporting(0);

echo "\n| Words  # ";
$words=trim(fgets(STDIN));
echo "\n| For Encrypted Enter 1 for Decrypted Enter 2  # ";
$type=trim(fgets(STDIN));
if($type == 1) // Encrypted
{
echo "\n| What is the key number .. Example : 10  # ";
$key=trim(fgets(STDIN));

function check($first){
   $first = strtoupper($first);
   $second = ord($first);
   return ($second > 64 && $second < 91) ? ($second - 64) : false;
}
function en0f($str, $add){
    $ar = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'); // u can add the letters big
    $strs = '';
    foreach(str_split($str) as $i => $wor)
    {
        $ifn = (check($wor) - 1);
        if( ( $ifn + $add ) > 26 )
            $strs .= $ar[( $ifn + $add ) - 26];
        else
            $strs .= $ar[$ifn+$add];
    }
    return $strs;
}

echo "\r\n Encrypted : [ ".en0f($words, +$key)." ]\r\n";
}elseif($type == 2) // Decrypted
{
echo "\n| What is the key number .. Example : 10  # ";
$key=trim(fgets(STDIN));

function check($first){
   $first = strtoupper($first);
   $second = ord($first);
   return ($second > 64 && $second < 91) ? ($second - 64) : false;
}
function en0f($str, $add){
    $ar = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'); // u can add the letters big
    $strs = '';
    foreach( str_split($str) as $i => $wor ) {
        $ifn = (check($wor) - 1);
        if( ( $ifn + $add ) > 26 )
            $strs .= $ar[( $ifn + $add ) - 26];
        else
            $strs .= $ar[$ifn+$add];
    }
    return $strs;
}

echo "\r\n Decrypted : [ ".en0f($words, -$key)." ]\r\n";
}
?>