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

ae89d59082d20bc06127fcd0efe6829660e2ffe07b45bd94eef92f3e3b7dfda2

Seed

c8eed21bf288bf18434afb92fac8a88e4eb207139de64e09839baf34a5aba7bf SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

412c18e6acff1effbdd04daf60b44d5e

Commitment

Batch 53,811, Merkle root be81605db50375eb57e98135eb7051d389d9d95c08bd3b9e9c874739c72cba18. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 543af821ddf2cb0dee45ac4603766924e3533e4e1bcfc16815a786e9544bbb97
2. f4e8a08bd8953452662c8d5b7a82e5f7f41fd3d9edf4efdc4881f5c416f2e852
3. 5a69e97ec9ca031281954d646f995ff51f332a4b2205ce80b52a485557813716

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.