Fair draws
How winners are chosen
Five steps, every draw
- 1
We commit to a secret before entries open
When a draw opens we publish a fingerprint (a SHA-256 hash) of a secret number. We cannot change the number afterwards without the fingerprint failing to match.
- 2
The list of entries is locked and published
When entries close we decide every free entry that arrived in time, then lock the list of valid entries and publish it with its own fingerprint. Paid and free entries are in the same list, with the same chance.
- 3
Public randomness decides
When the list is locked we name a future round of drand, a public randomness service run by independent organisations (the League of Entropy). Nobody, including us, can know that round in advance.
- 4
The winner follows from the published numbers
The secret, the drand round and the locked list together seed a standard random number generator, which picks the winning entry by a published method. Anyone can repeat the calculation and get the same winner.
- 5
We check the winner, then publish
We confirm the winner's identity, age and eligibility. We show their name only if they agree. A result is never edited: a correction is a separate, public record.
The random number generator
Winners are chosen on our server by ORVETTA-RNG-1.0.0: HMAC_DRBG with SHA-256, a generator defined by the US National Institute of Standards and Technology (NIST SP 800-90A). We did not invent our own.
It is seeded only with the secret we committed to, the drand round fixed when the list was locked, and the fingerprint of the locked list. Numbers outside an exact multiple of the number of entries are thrown away, so every entry has exactly the same chance.
Each version of the generator has its own name and a fingerprint of its exact code. Every draw records both, so it is always clear which code chose each winner. Nobody at ORVETTA can enter a winner, choose a seed or run a draw again.
- Version in use
- ORVETTA-RNG-1.0.0
- Generator
- HMAC_DRBG, NIST SP 800-90A Rev. 1, SHA-256
- Code fingerprint
- 88913358167da30cb3f01df0acfd2fd87f57648796e3d8af894152d24610869d
Independent testing
No independent laboratory has tested our random number generator yet. When one has, its certificate will appear here with the laboratory, the certificate reference, the version it covers, its dates and the document itself.
You do not have to take our word for anything in the meantime: every draw publishes what you need to check it yourself.
Check it yourself
Look up any entry on the results page, repeat any finished draw in your browser, or run our verifier, which fetches the randomness straight from drand.