anchor.diff:  
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
  --spec change_cell([cell()], pos_integer(), integer(), value(), cell_operation()) -> [cell()].
  +-spec change_cell([cell()], pos_integer(), Key::binary(), value(), cell_operation()) -> [cell()].
   change_cell(Column, CellNr, Key, Value, Operation) ->
       {HeadL, [Cell | TailL]} = lists:split(CellNr, Column),
       {Count, KeySum, KHSum, ValSum, VHSum} = Cell,
       lists:flatten([HeadL, 
                      {Count + operation_val(Operation), 
  -                    KeySum bxor Key, KHSum bxor ?Check_sum_fun(Key),
  -                    ValSum bxor Value, VHSum bxor ?Check_sum_fun(Value)}, 
  +                    util:bin_xor(KeySum, Key), KHSum bxor checksum_fun(Key),
  +                    ValSum bxor Value, VHSum bxor checksum_fun(Value)}, 
                      TailL]).
   
   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
positive.code: -spec is_pure(cell()) -> boolean().
  is_pure({Count, Key, KeyCheck, Val, ValCheck}) ->
      (Count =:= 1 orelse Count =:= -1) andalso
          ?Check_sum_fun(Key) =:= KeyCheck andalso
          ?Check_sum_fun(Val) =:= ValCheck.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  
negative.code:                                 RCC = resize(CellCount, K),
                                  {RCC, erlang:round(RCC / K)}
                          end,
      SubTable = [{0, <<0>> ,0, 0, 0} || _ <- lists:seq(1, ColSize)],
      Table = [ {I, SubTable} || I <- lists:seq(1, K)],
      #iblt{
            hfs = Hfs, 
  