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

89fac8c780504ae3786e70e2a236c06235c78301768568ec2543cd34d21fbd66

Seed

ec58cc836a39abb4bf769cef2c3f20d67bad7046e21ee8c915d54a1d12b33f8b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a02e5f121405161955e73841caacbe99

Commitment

Batch 68,248, Merkle root 4028a9a967ab1323e645bd46a06750ffe00954f42725d468b716e5b14a905ae9. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e63c2964429330b8a0cac00659c2641bd4a4fce6cbeaa43fdd4fb775df0b1dc5
2. 808196d2d601605f0c7e7d55ff2898ca5974dd29474541a5c4e0899f81ab6018

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.