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

11ae14afb0fd3a3c859ececda5d1ba16bb7da3af16468255733721fc9d5db8b1

Seed

3f11f76f42490aa1e8b23062bc3c55cf1246a48ec63da5006ca4e9714bf48dc0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7480e5c0ca49bdcbe33f98b0be0eb846

Commitment

Batch 60,439, Merkle root 1f40d3cf488fe0688615f9c743d39d1d905a6bd33d214fdda2f5db85d77b714b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 559fd772c142224974c8985a3745b3893d442c65f563e4b18068bdc628dfaf18
2. 6d6a34ff259664c4645976ce64aad3ea263e314fa816ef881159135d1ef3afa7
3. e1141dadef645b4ba92bb1c28b8b94efaa60264a78295d5f4a48cc892962c518

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.