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

599154b4703a56b0e5d34b02e2c25b03b5c642ebf86900291cb38460e4e96cca

Seed

7a3b0f71aca2ce369b6a0006209a67c0a6213779b82bb8616134b9173822daa6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cb07d5b29a98b4ee029b11a2247d7d94

Commitment

Batch 57,744, Merkle root f2049f7d85446c3efb5c61587adac4809cf399486ebcad7666e7ab4bc9d8eb09. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 94030d419a6497d8ca30ac8e7fa9d2a70802b246080cc53b3eb3fbed8f3caae0
2. 5e163dfde86dad6c041809b6d6e3fcd023aaa7e8cbc8b81453b452e39470bc0a

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.