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

5fdaadfadfb713961f9a978d533a6bd5fb7f587bcb6c7b1622fe7f49b3cf85fd

Seed

8fbb451a7d043aa62f4315831059301b5d7401c593e0651d4ec04eec033f7d5b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d8e91accbe6b4da227bf261eb89cd30f

Commitment

Batch 70,805, Merkle root 2f390878f3d2f993410a01bac65ea750bb4f871aad1d3d41b5d349031e30dca8. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 94880dc9bad6c1239784720a00b5b9b3bd0724fc96c3250895ba31282d5a67e9
2. 031cfc41a93c7aa71c9c3bde3bbeaa65bd05869da2eeddce15d612223454df97

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.