Club 100 / The draw

How the draw works

A 100 Club runs on trust. Members need to believe the draw is straight, and the treasurer needs to be able to prove it, especially the month a committee member wins. This is what Club 100 does when someone presses the draw button.

Who is in the draw

Only numbers that are held by an active member and paid for that month. The software builds that list from the payment records at the moment of the draw. A number with no payment recorded is left out; a member's number is never dropped for any other reason. The eligible list is saved with the result, so anyone can see exactly which numbers were in the hat.

Where the random number comes from

The winning position is requested from random.org, which generates true random numbers from atmospheric noise rather than from a formula. If random.org cannot be reached, the draw falls back to the operating system's cryptographic random number generator, the same source used to make encryption keys. Which source was used is recorded with the draw. Neither can be steered by the person pressing the button.

What is recorded

Every draw stores, permanently:

• the month being drawn
• the full list of eligible numbers, in order
• a fingerprint (a SHA-256 hash) of the month, the eligible list and the exact time, taken before the random number was requested
• the winning number and the member who held it
• the name of the person who ran the draw and the name of the witness

Which random source answered, and what it returned, is written to a separate audit log at the same time.

The fingerprint means the inputs cannot be altered after the event without the record showing it. The witness field is not optional.

What the software refuses to do

• Draw a month twice. Once a month has a result, a second draw for the same month is rejected. To re-run a month, for example because a payment was recorded late, the first result has to be voided by hand from the server, not from the admin screens, and the void is written to the audit log with the original winning number. It cannot be done quietly.
• Draw with no eligible numbers. If no payments are recorded for the month, the draw stops and says so.
• Record an impossible result. If the random source returns anything outside the eligible range, the draw aborts and nothing is written. This check exists because an earlier version of the software once recorded a fault as a result, and it was caught by exactly this kind of review.

What members see

The winners page on your club's site lists every month's winning number, the prize, and who drew and witnessed it. Winners are shown by their initials, not their full name. Members who want to check further can ask the treasurer for the draw record, which contains everything listed above.