The weekly lottery

Tickets

• Every 25,000 gp you burn at the well buys one ticket. The well takes whole tickets only; anything left over stays with you.
• Burned GP is destroyed straight away. It is not held anywhere, so there is nothing to refund.
• Each ticket is a line of 4 different numbers from 1 to 60, like 10263558. Pick your own or take a random line. Lines can repeat, including between players. Tickets only count in the week they were bought.
• More tickets means better odds: holding 10 of 1,000 tickets is a 1 in 100 chance.
• The prize is 50% of all GP burned into the round. The other 50% never comes back, which is what makes the well a GP sink.
• Every ticket holding the winning line, all 4 numbers, gets an equal share of the prize, rounded down to the gp. Two tickets on the winning line means two shares.

How the draw works

The winning line comes from three inputs that nobody controls alone, and every one of them is published here, so you can recompute the result yourself.

1. A sealed seed. Before the round opens, the server picks a secret random seed and publishes its SHA-256 fingerprint. Changing the seed later would change the fingerprint, so it is locked in before anyone buys a ticket.
2. A public ledger. Every ticket is listed with its line and the character holding it, and every well burn with the GP it destroyed. At 20:00 UTC on Sunday the ledger freezes and its fingerprint is published.
3. An outside random number. The draw uses the first drand quicknet beacon published 60 seconds after the close. drand is public randomness run by the League of Entropy. Nobody, including ONYX staff, can know it before it appears.
4. The result. The server reveals the seed, joins the seed, the beacon and the ledger fingerprint in that order, and takes the SHA-256 of the result. Read as a number and divided by the total tickets, it leaves a remainder. List the tickets from lowest line to highest (01 02 03 04 first) and count from 0: the ticket at the remainder’s position gives the winning line, and every ticket with that line shares the prize.
5. Winners collect their share in game from the Lottery NPC. The round’s seed, beacon and winners stay listed below.

Staff cannot pick a winner: the seed is fixed before tickets are sold, and the beacon is unknown until after they stop. Staff cannot hide tickets either: every entry is in the public ledger. Every round with tickets has a winner, because the winning line is always one somebody holds.

Picking a popular line neither helps nor hurts. A line held on more tickets is more likely to come up, and splits the prize more ways, so each ticket’s expected share is the same.