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

36d952c1aade5228dbc764ace1e04e927f2222c35ebf372cbdee53be8c3f6f56

Seed

79304c27673f3f859057feec7655013cabe63f0aae71e48b225903dcba2a0cc8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

42b54135792c101b8c9e0697a5a431e3

Commitment

Batch 48,634, Merkle root 45c44de9528e60626d3b2c48956bb9472ebda753ec72453ec4affb42e6b1bac9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f575ccfa693300d2c358a613650662751bbc6c49cb3c9cbbed11061fc74868dd

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.