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

e6923fc4bf29b6539693fc550bb86d1b0e5c44170e08fad2a7438131c18fd649

Seed

f720afa8b700f55258492ff83f13928c3a296e5d29433b447572c8e8bd89f37e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cfe8f15e93c8b60788cbd19e2637d2ee

Commitment

Batch 61,086, Merkle root 3e06584bb61f3393a291cb947a5e19d28059c52ea133bc479a7b18ea6c251575. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 790fe72bafbdfd82b5de781e01677c75f357401dacc1c2ade7ed71b2c52aa2d6
2. f1ea18e9f30db14da81b5f3d047a28d3bad76f463671092ee683708b3b6bd9ca

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.