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

2b129bcdd5ea5eb87b67f84ac5292c797f09cf3b975c12043817cd71b008e5d9

Seed

7fb93f7367cd7c589a24de3675eb099e1d47755fe86772bef2aead59d7a0ee5a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e5cb6b8f3742df38166bea6ff2471bce

Commitment

Batch 56,468, Merkle root 92720cbfe161e84f47be37b3a9c8cef1820237201b0426ebbb5cff6ce41ea523. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d778630a45f8925932d0782059151b3c042b5c494a2c9f49606415fae1d7d614
2. cc3c9d24045c85b844368ec66e3a68a0a6e1eb19afa9313607e547bf338561e6
3. 6a2414a6aa2f716c0a702d33e3481679b6120e0606da71089ba61f61f8d9d264

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.