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

2000d9d6dd7c0c1324d28871ce8a28804454374df02d080d144a076c16a32411

Seed

622f356b934ed04274c53290040f24ee23bf9f80841ac26cc5bf54fdd1c02df7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

11525b10384da0b7ca5c87d46dc791ef

Commitment

Batch 66,564, Merkle root 8055fc8888f9d5b77cd96e7a5793e9f5fb994967f3dd7436bc05a0c2072749aa. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 9c7ae3958a26ca3486132374854dc49b86311ca43cb10337362957fadc340804
2. 45d97a062d386d23a8a6dd1bdbdb643f28dc49ed96a6adb96017a7b6c5087e14

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.