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

6d4f1d4f9cea8434ec36c007b791de7f81c81ca233c40c63556ef60e88fd12f1

Seed

4abeaca13e1fe4d6abb6b8646a2a12446684e2a5f47bd9471961d444b1abd969 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1c437e0f39597e3f7d731e995497d277

Commitment

Batch 57,836, Merkle root 7d5298d3ea5f3fadf0df122798b911a416c8fc5c67b1d8a64d2659fbea114ea3. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8247c3c33c33ac97b8550cc4b0935d7f5f8dc30791449c2cb392bd2c8b16380e
2. 284ea9b5d1f676460e86a75e483543fef15f74dc6b553843161a11d67f981acf
3. 00ad06787a972ab684be9eaa8d7264dc7fc928d36becff8b9378ec509b48dbbb

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.