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

f6f53c4012b00f5bb3915359b2a2fb9d5f559de4ee4470117ceb87db69cda2b1

Seed

617e1d1971cfafb45043b74ecdd2e1344ce653a539004024493760c72ce0896d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fe5faeb2a316ea6adb0fd9f317c4a4a4

Commitment

Batch 47,517, Merkle root d1fb5c32e0e68c4ed692a1ed80cfcd69b1cc322883df73c75a2910f84c5fe130. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a232066f5336f0eb8acf98c427f288964a48fb19aff616892b4a49deef31f9a8
2. c5aa205394349cb60eb85a01229dab500263ddacfbb21255f38dcdc35a012c5f
3. 8e4ca5a167cb5605d6d1669da08baf0a2b54404fcb933a13731fb17e13e6cd85

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.