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

8f3415a2fb8f29f6a83617ae65c6ca4a0475014302999b99b31db5d4861e21a0

Seed

92ed195d089dcf7a7ef5e0bfc3d82e19991e6a28a8e2463cf64b55cb9afc63b7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

602a4e7dc4bc2708bac9cf7e9a277e31

Commitment

Batch 51,244, Merkle root 4bd4b6b57d488f589d52da5a50a6cb1b77e4e73f334e38e52573f66d3f7d333c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7e8769c8931e27f1f9db89f553f579a96f3536750b319fedc6dc88451b59212d
2. bd54373178f87a3c05115d7471345cefc10f9f9518fd6daff61cc1eb09968330

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.