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

46ff44235a9245091493faba898cce426bd834b53d6511768769d02fdb84828c

Seed

27f710131bbebad2aed744e1e7a533d1f72ccc8b024a589cc6867a7075a68237 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

62a96e6e2dc00a49a92babae227c303b

Commitment

Batch 48,453, Merkle root ea4c266783d7c5749f5057bc2c44f33e40f12d80939812b1b1a0152661eddb46. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. eca49c32b9c217681979f1594bad2691f48bf23467d1176ec8222edf7fbf9eb6
2. 17304d28391d56e209079d0331e5f126f4554334293e19c8707eadc4da73e2da

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.