code: function decrypt($data, $password) {
          $data = base64_decode($data);
          $salt = substr($data, 0, 16);
          $ct = substr($data, 16);
          $rounds = 3; // depends on key length
          $data00 = $password.$salt;
          $hash = array();
          $hash[0] = hash('sha256', $data00, true);
          $result = $hash[0];
          for ($i = 1; $i < $rounds; $i++) {
              $hash[$i] = hash('sha256', $hash[$i - 1].$data00, true);
              $result .= $hash[$i];
          }
          $key = substr($result, 0, 32);
          $iv  = substr($result, 32,16);
      
          return openssl_decrypt($ct, 'AES-256-CBC', $key, true, $iv);
      }
docs: session decrypt AES 256
  
  @param data $edata
  @param string $password
  @return decrypted data