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

2d65fea68f96f15f8dfa530d9ddc010e9612defb26268ef0e761cb7e90fffd52

Seed

5d84a922dbef83566bd90f92d62916ff8a6575b7b1cafd0b6ecc99c5504f0815 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f64e395bbf36e1925b7ddb4ca91355db

Commitment

Batch 55,747, Merkle root fa4972ceaf3961de45429504825b285b93c2df1d7cda243731e289b38dfd9583. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 49c99c36ba879fe61265a0a6750fbe78e939125587dc70179f3bcea922601b6a
2. 6819b122603227be25274563e1d5c83cfce04580e32fbf953be9c84453e0fd52
3. a25e1ab03271ec16cbfcecefffc3f5bfe07405842426510c0052156df9bb8442

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.