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

b203b3dd37774d85c77ae255affa4adcef1bf7d6f923fa508370c92d9363dd87

Seed

5c3e8e6ef1980fd7c49ba4f4540fdf29949821a176a443800d4805ac549e9eeb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

aec1cb6ad8c47347f8f0cafce174e1de

Commitment

Batch 53,739, Merkle root 38ddbf8e56781b22efd14df9d98a2baa4ab04e44d2acb12687606db6a559ff1f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8292ec5ea84d41aacf8c11a13c38ae70088d8977307edbe3737d51dfd17232d7
2. 836e38cc58b14f97d699b8e53db1afd10104d2658ee5d85c26d0d7427734fbb9
3. 4defb4a80512b1b6a7774b0894f693d37e849ea56e78911f251d93e3e2e27114

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.