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

45dedce22c23420803df1f832929ad8b6d2dd6ce3b8af8ca49c1837ed67a926d

Seed

a2242c7bf57ac96e8f88100d831cd656cc4434e9ea44af3efd9d8e375168f8a4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

26461cfab0aaca8c6169e5af0c600738

Commitment

Batch 60,114, Merkle root 2ab3bdc918aceeabd537a90294ee50e6062895b139f2990097fa593e367fbb94. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. aacf3ff137b5dbf937f83c0382ead1db92522ea688b058509253d4f4bcd9da54
2. 4df14dee42de75183fb914345f5e85c1063c604f290eac9ef9f9404f69b2b7df

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.