ROT 13

From CodeCodex

PHP[edit]

  /**
 * ROT13 is a simple function which rotates the 
 * characters of a string 13 places forward.
 *
 * @param     string    $string         Input string
 * @return    string     Encrypted string     
 */ 
function Rot13($string){
 
    for($i=0; $i < strlen($string); $i++) {
 
        $c = ord($string[$i]);
 
        if ($c >= ord('n') & $c <= ord('z') | $c >= ord('N') & $c <= ord('Z')) 
            $c -= 13;
        elseif ($c >= ord('a') & $c <= ord('m') | $c >= ord('A') & $c <= ord('M')) 
            $c += 13;
 
        $string[$i] = chr($c);
 
    }
 
    return $string;
}