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

2705109530850d1eddda772608734d947c73bfb32c5a8995f29ad13bb2aeb94b

Seed

11d094b4d93c8460566266996213106de38896126cb537433b9770fe5583fd48 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8b42efa1b14f3e2eaa38fb030ada41c5

Commitment

Batch 71,440, Merkle root 74b4a6a7bfeea5d81abfecd4be4659c6c057c6fa382b04a2e576a8f077412e62. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f3cf126b80bbeee504ef81deb626ba6a34a7d9931924bda63c8ea5da020a5b9e
2. 5d923f4dd3955cb5d9e75bf3aaee6ec0cac8af765010ae96898640cca4e939c9
3. b617c7a8bf661f5778057c482f839da6703e89c26b9d7381f833d2cb133cb1d3

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.