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

aac107c91c2a20b975032fc2227ffdafba292ccb0d81b280e131b712094f1797

Seed

9a40f299d4040cc9348d780b42ac6e177caadab080d79dd88cf1807a05fee43e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8c8c6c522caf5069a60cda2a6d8cb2b4

Commitment

Batch 70,020, Merkle root 5add040b7fcae1e85df6cefcf43544ce8a6be60a25c64cbe905d9ddac994bfea. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. c6962bd85a99dd1f942303e8bdeca374aeacfc1b8f857a39db11a5862b4569f1
2. 1838d0e6ac344c497ef0584090da177502b2fc1141bd49e4447a8bce52fdb4bc

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.