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Seed commitment

Published when the raffle was created, before entries opened. The revealed seed for each draw below must hash to exactly this value.

How it works

1. 1 At creation, a secret server seed is generated and its SHA-256 commitment is published (above). The seed itself stays hidden until the draw.
2. 2 At draw time the seed is revealed and combined with the full entrant pool to derive the draw seed: SHA256(server_seed + "|" + snapshot).
3. 3 Each entrant gets virtual "slots" equal to their entry count, and the draw seed deterministically selects the winning slots.
4. 4 Anyone can confirm the revealed seed matches the commitment and replay the selection to reproduce the same winners.

commitment = SHA256(server_seed)              // published before entries opened
snapshot   = "id:count,id:count,..."          // eligible entrants, sorted by id
draw_seed  = SHA256(server_seed + "|" + snapshot)
slots = expand entrants to slot pool based on entries_count
for N = 0, 1, 2... until all winners picked:
    // rejection sampling: redraw instead of biasing low slots
    for attempt = 0, 1, 2...:
        value = parseInt(SHA256(draw_seed + ":" + N + ":" + attempt).substring(0, 8), 16)
        if value < 2^32 - (2^32 mod slots.length): break
    index = value mod slots.length
    winner (position N+1) = entrant owning slot[index]
    slots.removeAll(winner's slots)