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

07f89026bd839a49e6423643deea9938130898d316649e32de52320db3731793

Seed

d2035ef2741605d0b81e7f299b693b108f67f676e5be20db1553c48fad9d59d1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

798d92b1a807fa0460d48b07ff6af674

Commitment

Batch 68,141, Merkle root 07ab067a4b2ae4daaff9b0a40c1fb236e1df29fc5058d308949dee833017b57a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a7fd1dc42f0578323170f5f0eaaeb464766f36304cfc07fa84b9dbfd51066c7a
2. 5e52306ced0374f5c37919be2af604f30006e8fe8bbb84bd617038130338c0b8
3. b7e049e6486ffc2eafd10e0282f3398c0dc1a5e3a132ccb5b7b0dfe4ea281415

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.