Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

48d755918e7292f9ec126c6b17921d699f5012ba15b413caa0ad62fc0b0f5e0c

Seed

762b18ef63ae845543b6caf76549a9ed4162b69bf388e2e458c76b1911778845 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8192011d18090bed1804032c0f2a2eed

Commitment

Batch 51,772, Merkle root 89d6be073a0b4ab0b637b31336fb8cdcfd013ab90e9ee946639dfcf6ef109fa7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fe321c962d3542b6e5d5fd95e02201db7282615c57247276a30250b096479ef7

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.