Say I wanted to create a system on the Ethereum network to place bets on a prize pool that was under the current block reward say 2.5 ETH.
Would these steps be a reasonably fair way to make sure players couldn't game the system?
1) Have 100 possible entries into the game
2) Gather all the player's address and XOR them together
3) On the 99th entry make sure that this person doesn't have a majority of the entries(multiple entries are allowed)
4) When the last person enters use the
block.timestamp function as a sort of seed to add to the number from the XOR'd addresses
5) do modulus division by 100 to find the winning number and hand out the prize
I understand that the block time can be manipulated by miners but if the prize pool is smaller than the block reward this is a feasible option, no?