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

acf16f0a4d125f95ee613b926ad9dba7f134715e2a2c2668ac4329ce6e622d72

Seed

dcfc9c8387d11270e8e7581ffaebe2f5a2df23481040bfc1ee598c6d321d45dc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cafc3230778f929b24de6ce7c29de3ff

Commitment

Batch 64,917, Merkle root 2a08cee45ef43d5249d112aac8b37b372b26f9517faf0f7591f9013c01c23e5e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3443330053154880e929089a775b5a623506b80986573c0697c7eb5ae0f09819
2. 688b96af019c6e04432bc793019afa862c7d16e1a4820918bd8f1b1195dfc4d6
3. 883b7397b93f6cb28f66eb702752f1cb309144a10e04e764f4925dcf16425c42

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.