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

26634731249897a7afac0467f29cc6763dd3265b0e82d6ca887357f4d814bc10

Seed

a3ffd92f436c40bd9c7b0b8c2cf129e98d6498dc7d5129e072e967d3fe5dac25 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

dc81eac67e611c56bedab20e98cbf80f

Commitment

Batch 50,811, Merkle root 351291d72671da285d7cbf8055e6eda42bef5519ce4294b413fa09aadcfc75ac. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. dadf297538b346c94cf3b58409b157cb624ec45f21af21af91ab8b94e82d3a33
2. 38b73dc5b473a1da8da98ccc0bb363495e0bea5820d44b99cfb242471b74ce95

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.