Token giveaways

Accounts involved

Each address is derived from fixed seeds (a PDAPDA (program-derived address) An address computed from fixed words and other addresses. It has no private key, so only its program can sign for it.), so the page can find it and nobody can swap in a look-alike.

The draw seed is sha256("veyduct-raffle-orao-v1" ‖ giveaway ‖ requester ‖ recent slot), with the recent slot at most 150 slots old. Because the seed depends on who asks and when, nobody can create the request account in advance.

Who can do what

• ActionWho signsRules the program enforces
• Fund the prizeAny wallet; it becomes the sponsorA prize above zero (not wrapped SOL), 1 to 16 distinct ordinary wallets, a request deadline within 216,000 slots and a result deadline after it within another 216,000.
• Request the drawAny wallet, onceAfter the funding slot and until the request deadline. It pays ORAO’s fee and deposit.
• ClaimThe drawn wallet onlyOnce ORAO has answered. The prize goes to that wallet’s own token account. There is no claim deadline.
• Recover the prizeThe sponsor onlyIf nobody requested the draw by the request deadline, or ORAO has not answered by the result deadline.
• Choose or change the winnerNobodyThe entrant list, prize and deadlines are fixed at funding, and the winner comes only from the ORAO-owned, answered request.

Once ORAO answers, the result is final. A won prize can never be refunded, not even by the sponsor and not even after the result deadline.

Draw math, with a worked example

ORAO (VRFVRF (verifiable random function) Randomness that comes with a proof. ORAO’s answer is checked on chain, so nobody, including ORAO, can pick a result and pass it off as random.) answers with 64 random bytes. The program turns them into an index into the stored entrant list, one byte at a time, so the number never overflows.

1. Fold the bytesn = 0; for each of the 64 bytes: n = (n × 256 + byte) mod NN is the number of entered wallets.
2. That is the whole number mod Nwinner index = (the 64 bytes read as one big number) mod NExact for 1, 2, 4, 8 or 16 wallets; for other counts the bias is below 16 ÷ 2⁵¹², far too small to matter.
3. The wallet at that index winswinner = entrants sorted by bytes [index]Only that wallet’s signature can claim.

Example

1. Three entered wallets, and the last two random bytes are 0x01 and 0x02 (the rest are zero).n = (0 × 256 + 1) mod 3 = 1, then n = (1 × 256 + 2) mod 3 = 258 mod 3 = 0The same as 0x0102 = 258, and 258 mod 3 = 0: the wallet at index 0 wins.

The Practice tab shows its 64 bytes and both calculations for every draw. Its bytes are derived from the draw seed, so the same giveaway always draws the same winner; real bytes come from ORAO.

Costs

VEYDUCT fee to fund a prizePaid once, in the same transaction, to VEYDUCT’s fee wallet. Shown in the review.

0.01 SOL

Account rent for a giveawayGiveaway (736 bytes) and prize escrow, at mainnet rent of 5,080 lamports per byte plus 128 bytes per account.

≈ 0.0059 SOL (Token-2022) · 0.0059 SOL (classic)

ORAO request feeSet by ORAO and read from its network state when you review the draw.

0.0005 SOL today

ORAO request depositRent for the 749-byte request. When ORAO answers it shrinks to 137 bytes and the rest comes back to whoever requested the draw.

0.0045 SOL, 0.0031 back

Network feePer transaction, one signature.

0.000005 SOL

Percentage feesRequesting the draw, claiming and recovering carry no VEYDUCT fee, and the program takes no cut of the prize.

None

Giveaway and escrowEscrow A token account owned by the giveaway address, not by you. The prize sits there until the winner claims it or you recover it. rentRent SOL that Solana requires every account to hold, sized by its bytes. It comes back only when an account is closed, and giveaway accounts are never closed. stays in those accounts: the program has no instruction that closes them. If the winner’s or sponsor’s token account for the prize coin was closed, the page re-creates it in the same transaction and shows that rent (about 0.0015 SOL) in the review.

Deadlines

A Solana slot is about 0.4 seconds; 9,000 slots is about an hour.

• Request deadline. The last slot anyone can request the draw. At most 216,000 slots (about a day) after funding; the page suggests about an hour.
• Result deadline. The last slot before the sponsor may recover an unanswered draw. At most 216,000 slots after the request deadline; the page suggests about an hour more.
• ORAO usually answers within a minute or two. An answer that arrives after the result deadline still counts, as long as the sponsor has not recovered the prize first.
• No claim deadline. The winner can claim whenever they like; the prize waits in escrow.

Edge cases and what can go wrong

FAQ