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

456e87e59aa17ce33b5fb2f904374f6d78f1d9e4eab3c07715e6be908e69b350

Seed

5c96fb66dde1bd96cd5184f181e3c6564ba9f81f8b5004ee6c112e37972d2aee SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9d4c5c4c07044a4a2238a20a62224895

Commitment

Batch 47,385, Merkle root 86509455c896ca250b676182195566a51e4794cc811494e67610e483a0cc8a61. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. cf51f91ce6db2c79bda07a5d023dc965ecfce656ec84a4fe0587f7d3a4f46de1
2. 19958614776a9ae1f6b7eb85086a153cd3b4c92e67e27196e89e618be3dca053
3. 19d98a026c9855bf95c08a87514337ab0653afe0bc47f56d63590ff592c4ed80

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.