(I was going to wait 6 blocks, but I got impatient.)
RESULTS
Block number: 453955
Block hash: 0000000000000000006c58a0ae184c4f68c894c5c25d67b97a795c87699993f7
Raffle ID: bitcointalk.org round 200
WINNING TICKET: 771
WINNER: YoBit
Congrats to YoBit!
This seems like something new. Very cool.
New, but only a one-time thing for the 200
th ad round.
Is block hash actually random? I heard some discussion about this before but I don't remember if there was any decent analysis done.
It's not random in the sense that it is uniformly distributed. This is obvious if you look at it because it always starts with a bunch of zeroes. However, it is basically impossible to predict the hash long in advance, so it makes a good
seed for generating random numbers that are unknowable before the block, but can be publicly calculated after the block.
Miners could throw away blocks that they generate or even try mining backward in order to affect the raffle result. However, this is very expensive mining behavior, so the raffle would have to have a value of at least hundreds of BTC to make this rational behavior for them; in such cases, you can adjust the procedure in order to prevent this attack.