A free giveaway you can verify yourself: a committed server seed hash plus a future Bitcoin block hash as public entropy. Every draw reproducible.
Most online giveaways ask you to trust the organiser. This one does not need you to. Before entries open we publish the SHA-256 hash of a secret server seed, and we nominate a Bitcoin block roughly a month in the future whose hash nobody — including us — can know or influence in advance.
When that block is mined, the winner is derived deterministically: the revealed server seed is combined with the block hash, and each entry is scored against the result. Anyone can recompute the whole draw afterwards and confirm both that the seed matches the hash we committed to and that the winning entry follows from it.
Public entropy has to satisfy two conditions: unpredictable before the fact, and verifiable after it. A Bitcoin block hash is both — it is expensive to influence and permanently published, so it works as a fair coin that neither party can weight.
The commitment half matters equally. Publishing the server seed hash up front means we cannot swap the seed once we see the block, and revealing the seed afterwards lets you check that we did not.
Every completed round exposes the server seed, the block hash, the combined final seed and the score of each entry. Hash the seed yourself and compare it with the commitment; then rerun the scoring and confirm the same entry wins. If either check fails, the draw is provably invalid.
Yes. There is no deposit, no purchase and no wagering requirement — entries are unique per round and per name.
Recompute it. The commitment hash is published before entries close, the block hash is public, and the scoring function is deterministic, so the result either reproduces or it does not.
Because the entropy source has to be genuinely unknowable when the round opens. The target block is set thousands of blocks ahead, which is what makes the outcome unpredictable.