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

3d94dbed035b25b3d1e5f2532ffe5ed6ee4efcf36256cac55ca38c9ee6530131

Seed

2327fccfc52da998c5b85e4e667ef8604613825d5edf7b466e7d5b60b992c77b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d9fdcf3c0f7b4164b5483f507ed48cd6

Commitment

Batch 62,109, Merkle root b5fb3b211b7f06768c06a83198641082e04fae43f3fafc5ccb6ae633c7650800. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c83f936cfcc0ed4b365d24c61ec5a7a987a924d3eb4fcef7431be8872383ed16
2. 6ea051ba0c568e837438062e51a939d1e893466df04ccb4490d4ce03ae8adf25
3. 1417fab9f1170c19430a89351484187d633c028e7554536647d97c82a200fe30

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.