E.S.P. Boxes

The magician asks the spectator to choose one of the five boxes which are in a bag. There is an empty folded paper inside in each box. The spectator takes out the empty paper from the choosen box, unfold and sign it. The spectator then fold back the signed paper and place it back to the choosen box. Finally the spectator puts back the chosen box into the bag and mixes it with the other boxes. The magicians digs into the bag and pulls out the chosen box with the spectator signed paper inside.

The trick does not require sleight of hand.
The boxes and the bag can be examined in the end.