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

d1f2f5bd52f995f616393e42b5e00c21a415ed72b31badada4e0ab19859d53a0

Seed

c87fb960043dea15fc486bfef7127edc5be7b2b0c2052ae4b97225f477c11137 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5ffab7f6aac2caf8d6645a763e50a131

Commitment

Batch 61,539, Merkle root 76ce6b269b059a0be43c62fdeab51948514b031c696ab3e8d72c2616b66510ac. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 46c4424a5f72db6eb9cb208092819cebf3c32835363ace3930464c5d0bc1de38
2. 7eca8e1a23e2f576f39598fbb94aea65b9a98dc889a72dd442912de9d4f59ed3

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.