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

c0afe23221d4eb9fd01765ffab0d211089798920aab78027fdedf24206cf159f

Seed

8837c6acf6aabdd62fb5a788e3ec2dfae4ad5302cdb12e8e60c9619921a4ec97 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3d5a3fedc903c9648610a957517eb536

Commitment

Batch 65,777, Merkle root 24f0e48ffd35d224f2246ab1191d3cdeb198a334a95a6ab8345698bfb035fa95. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. cee7db5d88662e59ff464856e123206ef35741b370bba5eb7023432b9927a9e6
2. c0dcd0c709ea8cb87379ecfe90a3f10fbb2eaf600f36377ff52be4eff2a54ae5
3. 7ce667206d3ded259a796591ef19b20c9a69c2cb3e6da22ec96ed99e4829554d

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.