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

b36229424a69276de92142b3e1d01d6369ba45104a821ec8b536341f4fb4ca64

Seed

b0acb1d5340b02f7ecc7389e51620d424edaca0e7951c8e2db4da268a4a975c2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6138dcded94471ef4152ba9008cbfb7a

Commitment

Batch 54,437, Merkle root 8ce8449698daf4394b5055084ed1d9e2c4e5fa8c0a23eee6bd0417ee341fff9e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7d4e2ea03073eabcb9c6dfdcec0c4673e54a91faef560a378bfb6205cca77e87
2. 37455ddb90e1d669cb55629edf109ffc87b802495f0ea8ff1736414803af571c

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.