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

aa4eb9065b964f4506aafaf993dab1fbe059ca8e5e51c0822a4bdf7e343aa2d5

Seed

225efe505ec292888d61db1c8197b08c66c6b23c8004799bf3fea52c89235844 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

08850a78d0cfe1848e243b7e71dacac5

Commitment

Batch 53,693, Merkle root 2b502455be1148c8a97245c4a95f8dfdc4d12c6d257e7da5c52f98c9c90208d2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 07483c75c52c64e9ac039885af542e6d309f280e539fb79e6f8cf22819db6287
2. fc6b2cd8d543af72fe020b6b4d3b8246b5cbd18ba404f7bcc40e37cabf02a611

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.