for($a = str_split( utf8_decode($a) ), $r='', $i=0; $i<count($a); $i++){
  $d = -1;
  $r .= chr(
      ord( $a[$i]) +
      ( $d*ord( substr(str_rot13('vOSnn95Lo8C1fDPMYKIUvrLcYZ8G699o'), $i%32, 1) )

      )
  );
}

@henriquekieckbusch thanks for the response! I'm studying binary data formats and was reverse engineering the `.csqd` format as an exercise. 

But it looks like its not even really binary. Looks like maybe encrypted JSON. Is that correct?

Are you saying that you just got lucky and noticed the `#` and `!` characters were being used as delimiters? Did you use any tools to  help spot these?