<?php
function enc($string) {
  $stringLength = strlen($string);
  $array;
  $returnString = "";

  for($x = 0; $x < $stringLength; $x++) {
    $array[$x] = ord($string{$x});
    if ($x < $stringLength-1) {
      $returnString .= $array[$x].",";
    } else {
      $returnString .= $array[$x];
    }
  }
  return $returnString;
}

function dec($hash) {
  $hashLength = strlen($hash);
  $returnString = "";

  $numberArray = explode(",", $hash);
  for ($x = 0; $x < $hashLength; $x++) {
    $returnString .= chr($numberArray[$x]);
  }
  return $returnString;
}

$encryptedText = enc("hey");
echo "Encrypted string: ".$encryptedText."<br />";
echo "Decrypted string: ".dec($encryptedText)."<br />";
?>