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

818548c28cbdfb8d7f36e9b19a5d5c411f02fce07da786fd667ad5a752317508

Seed

0553a5ed492de81f649ad7181707a7d47f15fddd7cb25d3b5cd304f1badbd6c5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5fa1da88c63489146f5aba6828927aad

Commitment

Batch 54,480, Merkle root f0bad44f1ada69f1e6e6b358c47e7fae842d2984449020923729200826756ec7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3167d1779608955629e3fef1d39b29c261f3206a6d99753a7e14e83354a515b9
2. 29b900286c68cf6b26b8e35d81c81945dc1128b532cd2bcaed8b52b55e8987d9
3. 22e22f0cedcef949c0d19154b25de813bcb2ce49785e08541b295b9a99762b12

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.