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

87ad434ea23aeffd195c59c8b54d25483087f2944c8ec96dabfee25d8225ec38

Seed

7cb7c16982f190d2057d360801acc8eab9d1bc85e7ec6f270f61dfe361b69b23 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

13b5b7045a4309e25ab881e91455a93f

Commitment

Batch 66,523, Merkle root 0313c37d34c390ed43edada13228b14a94fd83a1b83b8d4853a420a79ecc757b. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 24b9d6eae71ccc202eaf62778d8fdc26cffe3a885028c081660ce3da453ce920
2. c50cc8c712116aaad17ea197dad45cf5207a1028da5c8070ca2bc2f8831ec0eb

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.