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

1d60321ffee4ae0b56187d3e323ec113e4aaa44fcd38a3cfa145cce168492363

Seed

e9fb29a77a41169fc557ed22b872e79a921da77e5ea9fcac4904e45f6dc0c231 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

24651ec5505740ec6f7dec212cac40df

Commitment

Batch 59,572, Merkle root 91fd3b732df36f5e8e6e6c5ed62255e81ac1dbb957f1f75adc71d4716152feb3. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 0d53e0804e7cdd5947eae6db76b793bdd215f887b43c3ef11889e9b88eceda4d
2. 2cd9894189a27afe2a721f50fe52c90e79306cb6b82c8b3bce4fcd3cacf2df3b
3. 874502bd5c77b387c551b324dab06201c59bfa1bf41b824f4ca18f126f8f6eb0

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.