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

50af7507ae013b44605fe10675802ad06a345a3a201413d46c164d2832acca5b

Seed

aa7fcc6da8954f84b641a92cee977879decd79ead2a55c4f5538aed2024e01f8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3cdfe5d83b3cf51160b9f2214c416f37

Commitment

Batch 67,416, Merkle root cb3578b9ae9e776ff7a254fe00699af80392ddbb63b4b3c74fd326561cf72cea. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 954092b933f8dca8a9ebe41b2e10ccd73956febe9828c0de234757d0f68b0bcc
2. 04ec14bff63550430faac11d2a60f7e01c303dc2fe1ddbae7f331e53fe7f844f

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.