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

7e28fa95d9df4b282e7324694162cfda78d1d6f7c3d27c24cbc39e6a47e7493c

Seed

68944150f5313d84e286f8f50a76ab2fd9f163ca3890f5778dbb36c1b54ba12b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

036d22048665c99dc5424549af1cf022

Commitment

Batch 66,089, Merkle root 3ae1be3fc8f07f1a63cd40c63e4ef16810ce40d0a88695c1e2b1b6dc138d75cd. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 9d9ba91ca68d7c3249211ca3d75d6fd09d869b1395693601890d4eb382f6ff87
2. 08820b8ac8b94b251ed4cd1ebe0b50fea48fbfaf3ad7dabdfc6c9959a3d09e43
3. 6b6609d713684f32d45fa173419d3b1e4c35bb77d8383af98acf3775a57de251

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.