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

da57e9fd7d8d52656f6da6598e44edb70032efa70603359f1dcf7acf2857d641

Seed

d3deec09dccb9dcf73e47796dc8971d861d569d23d24a4550961638dfe45b0c0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

216be020b1e9c7a034aa771d6b121e1a

Commitment

Batch 69,671, Merkle root afc6f000d9f86eae2c1a39db09e9fc50d1cf358816ef21931d971c854af438df. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 1ef1c8dc623130d968eeccb11e1a21499af3a7d8b66ce654ac729ac5f6fe0cea
2. 922e83b14ada8ff0cb7ca7ef8b7768204410dc08a015139015c800dff306f694

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.