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

b6318fe8084fcfd0a819069a21cd61f6fc3ea897c50225cf93c4cc41f5e24541

Seed

a0d1dd9e113966b0f241f147b26c4652cf534593b81d909b0212fce358adf41d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c7be1ed8de0872b2e3e43d7555d37002

Commitment

Batch 72,008, Merkle root afd00069cc887641dfddcccf2e042952db3a8dc3ae037256533b3849cc14ade9. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. fada4022b82c141767afb832883de69430f1d2c5c3af713c62d33b094487e663
2. 9bf83cf5e736a8a806fecf4277b6d2f0a15b7287a0dd9f982dbb3068aeed6a12
3. 88e4120f7bc1428b6f9d4157e09ad3e557ddddbe05d0608a2b3fd0a0fb4d9db0

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.