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

6b4bcc7f4893a1c60fdd7e1613deaa0421165616aa71cbe3f135a1d55ebe7693

Seed

9484c02dfd88970e9eae4bec187dfac9b42773250070cb1feb114e26e1bcbab7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5620e21c5968ed5966bbc5b4fa723e30

Commitment

Batch 67,646, Merkle root c3f48a929f435ac119fa47d293e755521ef40e08a74cdf69da86e896e4a0c2f0. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. eb56f6fcd6867eebe6d35363a763310d2e4a37462f122a292de541f661cc95da
2. edd40dbcefecc363924f24fdb8a66781027177041f983abd28f8520addf2d075

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.