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

d1851eeb44f5f4da18ff5e256461dd08d870bf0229ac9f54c8d4815043575b25

Seed

0ffc4f3b7beb958f1a8c14a74b10679ecb91948ff4a346450f07b2f77c158660 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

93361ba3f1fdccfde5054527e0a8b8f0

Commitment

Batch 67,438, Merkle root 0bc3eb8429ec3cca4d063227dee5a3f2e47770b4c869bac4d154c6f21956aea0. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 59722efb5a4482da109cb4c4062e33afa11d5334370ab16bfc68b82922528f47
2. a3392a273887eeffc3747a0a62fe40dda2c0e146ca3f8b7bca03fb38c98f7794
3. c653e763ea09224697a991a8015ca243f04b2f6e6a24910dbeedf291e13bfb4a

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.