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

f9605cbd7a191ea186fd4f4754203c8ba30488b2d07116aa131669cf1311bef8

Seed

4ccb5dbaf90abd2b354faf706799cabe323dd595bc7703aa0595be3e05d8a0bc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

06342030e8a5cfdd2b8fa464f04bd47a

Commitment

Batch 67,766, Merkle root 75ac45b0300cd8c7b068614029e1c9def79d442cd8a0a7870477794df95dd424. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 14a61d2c4e2d195ab3664f73a77ffc2198e032938eba2971c282e42819c7ee37
2. 6e6fac05433c1a409fcf4dbb65b2ec86945028a888549f086bc74c7489c8d6b6

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.