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

0cd2d137d5f3c12d07274b083ba2e416ec8609eda1196a0ec0c82ad39de8cd0f

Seed

845296ebd132c756f0a2d88fc7c151fe758127d63725a8a2bd36c78bd0d88cc5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1bb9a2d40c21718153609e36e522ecf5

Commitment

Batch 68,940, Merkle root f2947b65770cb0e979262b198bf3deacd1eba5be01b7765d56de700f0a5289de. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0c2001ec46f7ff9a9b97eaa7be40221891cf547a8901f2ef322c164cbf0c0cdc
2. e8b1931e4a9a33069da0bdaa76fdd569c0bb3bf3ee2d449d4300dee24a11afd6

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.