how the core one+ giveaway was actually drawn

the core one+ kit giveaway is done. the winner came out of the draw on saturday 5 september, out of 248 qualifying orders, and i am posting them the same way as the last round, initials plus the order number, so nobody gets named publicly for buying filament.

this post is here so you can check the draw instead of taking my word for it. every number below is re-runnable by anyone reading this.

who was actually in it

entries were every order from #40086 through to 11:59pm friday 4 september, sydney time. the published terms were $100 or more before shipping, not cancelled, not refunded, one entry per order, so repeat orders stacked.

• 570 orders in the window
• 300 of them under $100
• 9 cancelled
• 6 refunded
• 7 unpaid
• 248 eligible entries, held by 241 different customers

the window ran #40086 to #40655.

how the winner was picked

i did not want this to be me running a random number on my own pc and telling you it was fine. so the pick is seeded off a public randomness beacon that i do not control and cannot predict. it works in two halves, commit then reveal.

1. commit. the full entry list was frozen to a file and hashed before any randomness existed. that locks in who is in the draw and in what order, so it cannot be edited later.
   pool hash 48faa57c6ed2a88372522f89d35d87a3ba830015cafd6465ab34c60632fff234
2. reveal. drand is a public randomness beacon run by a group of independent organisations, and it publishes a new value every 3 seconds. i read the current round, then targeted a round about 40 seconds into the future and waited for it. that value did not exist when the entry list was frozen, so nobody could aim at it, me included.
   round 31925359
   randomness 70c80295b4ea44b9d8a6f2680839ac86b23fe47054ad212cdaa9d3f43b68faec
   chain 52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971
3. seed. the pool hash, the chain, the round number and the beacon value get hashed together into one seed.
   seed 9be2dad4c62b7328b572010ca2cb76cefd983bb20848ec5c70b45ccc80cb9a10
4. draw. that seed drives a sha256 based random generator and a full shuffle of all 248 entries, using rejection sampling so there is no bias toward the low numbers. every entry sits at exactly 1 in 248. the winner is the first entry out of the shuffle.

the beacon round is still public and always will be: open round 31925359 and you will get the same randomness value printed above.

the one thing you cannot rebuild at home is the frozen entry list itself, because it has customer detail in it. that is what the hash is for. it proves the list could not be swapped after the beacon landed.

what happens now

im contacting the winner on the email address from order #40282. that order already shipped back in august, so the printer goes out as its own shipment.

thanks to everyone who ordered. more printer giveaways as more containers land.

sidd