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

3a792a0f55cf59e0669d482ee4ed32726d7c87da1baddae30763d1c2759057b7

Seed

607170e569f1c3b38d38ab7874aaaf63b52a438ce3405d1f93f6711031570089 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cda254268f6eb0d9001175b99c042413

Commitment

Batch 49,398, Merkle root 0a25b9bddca0af67dc45c965d626bf98f1c47b27cb7b6ff1f55bffc68c4a1d04. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 33e607426a6d2139a3e4c4eca05ebfa04166d1dc7a551b07162c8118785322a2
2. a7eac0643dd1611d772ce99694a1942b139fec2856621f89ccb54a4ebad3fbf5

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.