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

90b38e72366602160c541568cafa63efc92eaea568a1c008150fce4703f8d346

Seed

1ecc53cfc881a64b5536c9ecd10f5a8744f8967d41ab48e04d7e0111c471af31 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1637009ef071b73ba5de1f9d2717f66b

Commitment

Batch 58,530, Merkle root 90cbbb2d46f592f1ee4540e574d06f29f65d276b9aeb5fbffc7118f99c8d809b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 27760b3fd3bb6d38d4d12ebd5de5c76743ac01df19f7b33cdb2b1a2883a3aee1
2. e081ce6dd90537ee73cb0430f281b95281f6c0b9d342c33bc56d6b60e3350268
3. 4a95002a3dd1b6da4782ee38e1513f9facff8ccefea3af2da5c1a8ab1d18f464

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.