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

51f9e282c6d235c78e4b4e27f47cc380523a9c48a27e772919e999f14931139c

Seed

098dcc7497b311d4fc7c4c8ec6dfb3afaccc8e3047789d2a30143e1b4ca5cdaa SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b852fa9a7b8efdac7979399a8f4f8507

Commitment

Batch 70,410, Merkle root 79f596674a1aae7ada8533cb3ecebb724655fa724b40be26ba617af43dc8bc39. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. b405491065c80153d6bb448bea9c0e3c57a818b75da2995dd701f9fa967c5d8c
2. 3b54a257df6423701120d7c3a724a9f841d9ad04d9a97d145618aca85382ebcf
3. f67eff9a453c7e1c92215d438b797c7668018208841711890b4689c9d1c476e0

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.