In this Instructable I am going to show you, how to make a Lego storage box, that can only be opened if you know the trick. Ever since I have seen this official LEGO Storage Brick
I fell in love with it. The only thing that really bothered me was, that they slide open when you try to lift them (and the cut-out at the sides that is supposed to make opening it easier...).
I remembered this Mystery Box
by fungus amungus
and decided to use his concept, to make a better Lego storage box.
If you don't mind the cut-outs on the sides and the uneven bottom, you can of course add the lock to the original Lego storage box.