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How Provably Fair Actually Works (Without the Buzzwords)

Client seed, server seed, nonce, hash — a plain-English walkthrough of what provably fair really proves, and what it doesn't.

How Provably Fair Works

Provably fair systems give you cryptographic proof that an operator didn't tamper with the result of a game.

The mechanism

  1. The server generates a server seed and publishes its hash.
  2. You provide a client seed of your own.
  3. The game uses HMAC(serverSeed, clientSeed + nonce) to produce the result.
  4. After the round, the server reveals the unhashed seed so you can verify.

What it proves

That the result wasn't changed after the round started.

What it doesn't prove

  • The odds posted are accurate.
  • The site won't ban you for winning.
  • Withdrawals will be honored.

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