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

758657265a3b6bd7aa579b33b7901f34538773819f79df36f383daa433d1177c

Seed

496b41b43818d49bdeff5e778c2092859dee7b7a07604fa3a08d734c256e5e3c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e249a2f0610285c3d8f10b59b80b05fe

Commitment

Batch 66,873, Merkle root 204721ed1840441bc843830a5897943db16e1022c41983586754b254bb8d3bbf. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. bf0bf061bd405e8124b7f1e2c4814741d537b486d4583bd637cb1b927d769a05
2. e859ceae11aebdef33e1860bbe3e84d03df91a16beaa2cccc856f715f875bf0e
3. 5c27359f5718334360cdaddbf913b0b08d554545f869d73d17488f1c8611adcc

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.