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

42869a33939260fb9bbcad13c3039aabf5939e57a8a673334bb036dd081eea85

Seed

22080fdc15b4efe4b2dfc3ebbb4cc24be8e954ee3d4b491ce3f8af991815872d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b48d564f6f693b79a073611b92a1f59f

Commitment

Batch 67,670, Merkle root e60bc101b64470dd67234519cdbe332db397db65f8ddbdec53a6c3ac4b4cbfd1. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 77334a60818f0ab293a77981dce12ebfb37769efaa26d2d5459ceee9b3370b74
2. 6b2689d927063d5b92d64f6c2a4f13737d4f42ad440de5392f79a370cc633261

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.