Random Selection with Verifiable Receipts
DrawLuma is a fast, clean suite of random selection tools designed for educators, organizers, game nights, and everyday decisions.
Our Philosophy
We believe everyday utilities should be joyful, fast, and completely respectful of your privacy. You shouldn’t need to register an account, navigate intrusive popups, or hand over personal rosters to make a simple, fair draw.
DrawLuma runs directly in your web browser. All calculations, animations, and name lists exist in local device memory and are never uploaded to a remote database.
How Selection Works
Cryptographic Entropy: Every draw initializes fresh random entropy using the W3C standard crypto.getRandomValues API built into modern browsers.
Rejection Sampling: To prevent modulo bias (where certain outcomes might have a fractional advantage), DrawLuma applies uniform rejection sampling to guarantee that every single eligible entry has the exact same mathematical probability.
Duplicate Entries vs Unique Names: DrawLuma treats each line as an independent entry or raffle ticket. If a name appears twice, that participant has two chances to win.
Multiple Winners: When picking multiple winners, draws select entries without replacement so no individual entry can win twice in the same round.
Team Generation: Teams are formed by shuffling the complete roster and distributing members sequentially. If your participant count is not evenly divisible by the team count, group sizes will differ by at most one person.
What Verification Receipts Can & Cannot Establish
What a Receipt Proves:
Each draw generates a downloadable JSON receipt containing the cryptographic seed, timestamp, algorithm version, input list, and outcome. Anyone can upload this receipt to DrawLuma’s verifier to mathematically reproduce the draw and confirm that the recorded seed unequivocally produces the recorded winner.
What a Receipt Cannot Establish:
A receipt proves mathematical correctness of that recorded run, but cannot establish whether an organizer conducted private unrecorded trial runs before selecting the winner they wanted. True transparency in high-stakes giveaways requires recording or live-streaming the selection from the very first attempt.
Questions & Vulnerability Reporting
We welcome constructive feedback, bug reports, and security disclosures. If you notice any anomalies in our randomness or cryptographic verification, please reach out directly: