It's useful to create an trusted random number. In the centralization world, it's impossible. Now we have chance to in the decentralization world.

Now,I provider some examples though they still have some problems.

  1. Not predicated block information.
    It's general used in DAPP and lottery. Because the blockchain producer can't predicate. So we trusted that the future block information is random. In fact, we know that the Fom3D game was attached by the hacker. So there is still some issue to solved.

  2. Random number based on the cryptography.
    For example, first player A provider encrypt random number X with signature. Player B provider encrypt random number Y with signature. Then player A andB provider X and Y, and they can validate the number by each other. So the random number is (X+Y).

TODO You can also provider other solutions. any advice is welcome.