Transparency
How our provably fair draws work
You shouldn't have to trust us to pick winners fairly. Every draw can be re-run by anyone with the published seeds, and you'll get exactly the same winners.
1. We commit to a secret seed
When a giveaway is created we generate a random 256-bit server seed and publish its SHA-256 hash on the giveaway page. The hash locks the seed in: we can't change it later without the hash changing.
2. Entries are frozen into tickets
When the giveaway ends, every eligible entry gets a ticket range in entry order: 1 ticket, or 2+ if the code bonus was verified. This list (with masked usernames) is hashed and published.
3. A public seed nobody controls
The client seed is the hash of the first Bitcoin block mined after entries close. It's fixed by the end time, so it doesn't matter when we press draw, and nobody (including us) can predict or choose it.
4. The maths picks the winner
For each winner we compute HMAC-SHA256(serverSeed, clientSeed:entriesHash:nonce), take the first 13 hex characters as a number, and use it modulo the total tickets. If someone already won, the nonce goes up by one and we draw again.
The formula
hash = HMAC_SHA256(key = serverSeed, message = clientSeed + ":" + entriesHash + ":" + nonce) ticket = parseInt(hash.slice(0, 13), 16) % totalTickets winner = entry whose range contains ticket (already won? nonce + 1 and repeat)
Verify the draw yourself
Everything below runs in your browser. Nothing is sent to our servers.
Tip: every drawn giveaway page has this verifier pre-filled with its real seeds and entry list.
Provably fair FAQ
Can Top Case Sites rig a giveaway?
No. The server seed is committed before anyone enters, and the client seed comes from a Bitcoin block mined after entries close. Changing either one would break the published hashes.
Why are usernames masked?
To protect entrants' privacy. Each entry also has a unique entry ID, so you can find your own entry and confirm your ticket range.
What happens if a winner doesn't claim their prize?
We reroll. A reroll is simply the next pick in the same deterministic sequence (the next nonce), so it is just as verifiable as the original draw.
How do 2x entries work?
If a giveaway has the code bonus enabled and you used our code on the sponsor site, your entry gets extra tickets once it's verified. More tickets means a bigger ticket range and better odds.
Editor's podium
