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

5a4f476e7ece31337e09aa43a285a8f3f56f987568d776dc4a59930f8cbe3b2f

Seed

147941d03af16f0a148c79e2060681eb4c8bb9fd994d2a57232e6036076c32c4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bcfecf3dbfacf9166a1ea0de22793ec2

Commitment

Batch 66,173, Merkle root 1762630280afe8dc47140f76a07ea249e9e8c185545792f1f02ed3793aede31f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 5a743a3359d920d99ef7ef2778a04a78e2c1e1ec41c30a2aad6e8d9ceb43b191
2. 503e5c0d028fff8d41943573886f90074fc2471afd3d03506db5c0e978bdeb8d

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.