1. Cryptographic Puzzle Boxes
Alex Biryukov
University of Luxembourg

2. Himitsu-Bako (Secret Box)
Made in Hakone region of Japan
From 6 to 78 or even more steps

4. Science Festival in Lux 2009

5. Not Cryptographic Boxes
-Simple flow of steps
-Number of combinations is not exponential
-Clear measure of progress (lid goes down)

6. Open problem How to make crypto puzzle box?
(Using similar set of steps and sliding keys and not like a combination lock)
Note that making even 100 steps by hand is hard

7. Open problem How to make crypto puzzle box?
(Using similar set of steps and sliding keys and not like a combination lock)
Two types:
Exponentially hard (need to know the key to open)
Trapdoor boxes (seem hard but relatively easy if you know the algorithm)

8. Some ideas
Make the slider follow a hidden labyrinth (maze)

9. Some ideas Make the slider follow a labyrinth (maze) Not very good:
You can draw a hidden maze
Solving a maze is not hard
Can serve as a trapdoor box

10. Better idea
Make a maze with two the sliders follow a labyrinth (maze). With fixed vertical distance between the sliders.

11. Other ideas?