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

63f8ba1dda7b775be6ecb353edcf29a12b510ced6848ce7531d1297e1bad343c

Seed

4f937ec3573d5801e542b5f8205ca83d12018ca32a949aa1b09981769f862f73 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cc1359d6340f312e4446cd05f1ddd11b

Commitment

Batch 61,610, Merkle root 45f6056e8a4fd99890b5f3f5ea67909b8e7fb8d1167bdd4f602421a9eb45d203. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 0d587e97a54cfd0ca671fbf3d27502ad341138529d97923fd63a68a8c724ba0c
2. a7952306f34510b550a3a83fda8652228001932340d98c2388649d174ce82a70

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.