lesson 1:
Why a Block Hash
Nobody knows a block's hash before the block is made. So: close entries at a block height, publish the entry list and its hash, then use the hash of a block a few blocks later. Anybody can re-run the pick and get the same winners.
GLiBz will run its free Launch Season draws this way (coming), and publish the block, the hash, the entry-list hash and the script with every result.
Safety: Never share yer private keys, seed phrase or wallet file with anybody. GLiBz never asks fer 'em, and neither does the QuarterMaster.