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

6515605de4f6ee45045b36ca6603a577746cd2c9314e8102aa308c729aaf7d51

Seed

1f23a98816911ea23353502dc664d295d26726f573781ecb01d3a14fa6e87ff1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ecb4bb3e1ab9a477e275c3762fe7e21a

Commitment

Batch 56,002, Merkle root d23f8600f28336d2a4f70cb292f0d13695562694fc0830d9a63cdeff67110bc9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fce805dd8cd9a92bdcc1dcc9749ded24ff7ba782ee8b64b4c23e5dd86f12436e
2. 16d741b29555178773719743ba179ca0296678f091148814f53b370f2a149483

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.