Secret message lock box

I made this secret padlock box for a treasure hunt with my friends. It may be useful to hold all your secret messages.

Here is the onshape link to the design: https://cad.onshape.com/documents/890f1bffc6f69b68fe83ba77/w/cf1cade1bd3dc7ddf7a748a9/e/e58d321a9d0174559b297d70

I add a bigger box to the files (75mmX60mmX5mm). This one is big enough to hold an entire letter sheet folded in 4X4. The dimensions of the small one were 25mmX25mmX3mm.