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

5a097d581f43dde7d91fd898d800e88f9a2ae811af9542fc21acb5e32bd0b011

Seed

d37e668fee50e87e3b136bbcbccc05969a064c3c15eb0baea2da146e4a1d583a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fc775a09e41ea17c69b15ec6086c06b0

Commitment

Batch 71,978, Merkle root 3a5b2f7ef5d06f3e0f057e953deb5d900c7d4985c9a0b10fc3f3053fba9ee492. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e9cdfc51eba557c18e3435085b363512c826303d07682e074195a80f59e5e0b9
2. a75348e14d7116af0b5e44f84157636498caa4d9325350ca19bab0a51c3ca9da
3. b7b7ab0909ecd4346321928d0cb5f512e499d770e7a7925ede61964eccf416f6

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.