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

4fd6299f839e79ac436414f427f66a56e459fe3f609688ae9cbfa05d5467b5d8

Seed

f6c3b1fd75b85ff1802b8f550402df66a5ba7f790c6aa8582623679d873f8b34 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a13e0caad07587645bce141e590fb70f

Commitment

Batch 64,007, Merkle root e3bf4a07f131322d476eb7c55478892a4a23ad9beb4d66a03810bdb9c76d7762. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. cb120522fd11863b2d2ff8dce82f559f64b3664b5143819f77848b41bb3ddd4d
2. c90947fc7960e3d460fd7e544a04aa8344758c4202effc16e6418c1052015585

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.