Verify a draw

Real proof. Not just words.

Every Beaver draw publishes the values needed to reproduce its result. The public verifier takes those values and checks them. Anybody can use it.

Try the check How Beaver draws work
Draw verificationVerified
Competition
Example draw
Entries committed
1,000
Entry commitment
9f1c…a7e2
Randomness source
Public value, named before the draw
Winning ticket
#0417
Status
Independently verifiable

Illustration with example values. A real verified draw record will replace it.

What the verifier checks

Three questions. Three yes or no answers.

  • Does the entry list match its commitment?

    The list is fingerprinted again and compared with the fingerprint published before the draw.

  • Was the randomness named before it existed?

    The randomness source was identified in advance, and its published value is the one used.

  • Does the winner recompute?

    Applying that randomness to that list, with the published selection method, gives the same winning ticket.

If all three say yes, you do not need to trust anybody. If any says no, you know.

The method, in your browser

Run it. Check it. Break it.

A working demonstration on 1,000 example entries. It shows exactly the kind of checking the verifier does.

  1. 1Commit the entries
  2. 2Reveal the randomness
  3. 3Select the winner
  4. 4Check it yourself

Entry list 1,000 entries

    Commitment (SHA-256 of the list)

    Not committed yet

    Randomness

    Named before the draw, published after. Nobody knows it yet.

    Winning ticket

    Pending

    Verification

    • Entry list matches its commitment
    • Randomness was named before it existed
    • Winner recomputes from the published values

    Press Run the draw to start.

    A demonstration of the method, running in your browser. It is not a live Beaver draw, and it does not use Beaver's exact algorithm or randomness source. The "randomness" here is a stand-in for a public value published after the entries are committed.

    A real draw

    Want to check a live Beaver draw?

    Draw verification records are published with Beaver draws. We will walk you through a real one in a demo, and you can check it yourself while we watch.

    We are adding a linked, real verified draw to this page. We would rather wait for that than put a made up one here.

    Book a demo

    Questions

    Asked and answered

    Who can use the verifier?

    Anybody. A player, a journalist, a regulator or a competitor. The point is that nobody needs special access.

    What if the verifier says a result does not match?

    Then the result cannot be relied on, and the operator has something to explain. Beaver's tamper refusal is designed to stop a changed list reaching selection in the first place.

    Can I reproduce the result without the verifier?

    Yes. The published values are enough to reproduce it independently. Our guide to verifying a prize draw explains the general method.

    Keep going

    Related

    We expected you to check

    Better competitions start with higher standards.

    Book a demo How Beaver draws work