如何保证每个游戏的公平性？

Overview

In our Jackpot game, each participant places a bet. Each bet allocates a continuous ticket range in the order bets arrive (e.g., if the first player bets 100, their range is 0–99, the next 200, their range is 100–299, etc.). The more you bet, the larger the portion of 0–100 you cover.

Once bets close, a random percentage from 0 to 100 (rounded to six decimal places) is generated using the server seed and the EOS block. We reveal our server seed after the round ends, so anyone can verify the exact roll number themselves.

1function generateTicketValue(
2    serverSeed: string,
3    clientSeed: string,
4    nonce: number | string,
5    range: { min: number; max: number; fixed: number },
6): number {
7    const chanceHash = `${serverSeed}-${clientSeed}-${nonce}`;
8    const percentage = new Chance(chanceHash).floating(range) / 100;
9    return percentage;
10}

1import { createHmac } from 'crypto';
2
3function deterministicShuffle<T>(items: T[], seed: string): T[] {
4    const shuffled = [...items];
5    for (let i = shuffled.length - 1; i > 0; i--) {
6        const hash = createHmac('sha256', seed)
7            .update(String(i))
8            .digest('hex');
9        const j = parseInt(hash.substring(0, 8), 16) % (i + 1);
10        [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
11    }
12    return shuffled;
13}
14
15// Usage:
16const shuffleSeed = `${serverSeed}:${clientSeed}:shuffle`;
17const shuffledBets = deterministicShuffle(bets, shuffleSeed);
18// Tickets are then assigned in shuffledBets order

Jackpot Example

• Your bet secures a slice of the 0–100 range proportional to your wager amount.
• We generate a random percentage (0–100, six decimals) using the server seed and the EOS block.
• Whoever's ticket range includes that percentage wins the pot.
• Suppose three bets have been placed in order: 100, 200, and 700 (total pot = 1,000).
• A random percentage (e.g., 36.42%) is generated from our provably fair method.
• We multiply 36.42% by 1,000, giving a "winning ticket" value of 364.2.
• Ticket ranges: 0–99 (first bet), 100–299 (second), 300–999 (third). Since 364.2 falls in 300–999, the third bet wins.
• Because the server seed, public seed, and EOS block are revealed, anyone can replicate the result.