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

31cda478a2d7f160fc751ff572b7d894f8b0a4703deee8fcb5fac09142be7819

Seed

b3ac65f203816388a450819f640387c7653360eeacb84b1a098057a1b440e3fe SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

042e46351914ac33584305cf24d5772f

Commitment

Batch 50,116, Merkle root c799bac6ca9a390b32a6def25b50f3f5415d81f77dcdeece2edef15328bb5807. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3fae56552ba3c45d4c03215444115a13d52666ec59f187051ae8ed02c7ca6a07
2. 3c2d7bac8bff9f3a54dadf1598ed27fa9334c57a091d6649a42a95e083b80c4d
3. e3070876eb8355e1db27dd907d2997a4edf1389200186a78d3d5df66a9fa501a

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.