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

3ce3ac3fa41a6f8c5b438888d6e062f81e74c27ecaab76cf82d399f523925e42

Seed

58f673ead4220919b9bce4d1804385119d24538028d54bde7989fb45bc891a95 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

39b9c5c9ecc76bb277ca3b431dd1ce0a

Commitment

Batch 56,994, Merkle root 42fb2d53b504b7fec8661d8e7742b2a69f11722fd37913c14b65ac89a214884e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a2621d4204aae9628ec327911f99506155de84b0b4d1a99844900f00b69c92ce
2. a500195bab1f2a23d0265a529b42cfb53c42c358829112b56f491cf1bf09566d

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.