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

cb1801cb0d3688eded6e3c9854e5731b5a51bc8a7fc5540fdae5a35d42735ecd

Seed

8cdaf5a42e62e56f6789c2a6f03881353116663ede545b926859d174d25d336b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e8f4ba8538001dd1530e7b6a62858897

Commitment

Batch 53,457, Merkle root 77248f8e285f0881302a05e52c86bd36b026975cec395246f3f2e5eb96eb0697. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 44c3f061e61a1e7a1e9a793d326c91b20f55504573543cef86f480c13cad181d
2. 87aba8339ef8964ae090e6ed969ecca2422005af68995d6f8e74c5a366e5d8a5

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.