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

8813dc833802be6a434124d2bf70da236ca8e1a4722d379a1788159c44d1e222

Seed

f2a750a346244e2a6c7b6da26bc5cbd92de10597e89d7aed61ab204a06461865 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4b13955ae73d43c7e43e3fbee3948657

Commitment

Batch 49,276, Merkle root 7ea2d8bf6fab924b03a6295bc63bd48220aaf93a603ff5dac093b3eaa179df82. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 89070a689c0d4d8ea4c30f647ce5390d7e13568a5df2309245d960b94cd9ba03
2. d17df6409971ed1ee94d909084a85308b63852f467e2b4390f2e54fb681796f2
3. 04ff630fed72bd097234653947c43579692785a9f9d8eb267572723b149ec790

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.