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

d24ae3f0aa04aec3de77063a40815eb77100125d15327650425ebfdc0fbdfd32

Seed

8eca5007f625a6b475b7c2c9e6bfb98dfe27437fcf6f28e92e41ba52c6f7db27 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1c8dc7a9823ce847f4b0584b72617bed

Commitment

Batch 63,712, Merkle root 972540ce49664772b09bae143a3b0151617e98f6683c7a1729e554886fce8b94. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 52deadd11f715a224c7968fc6640e35bd3d4f978eb18012ef575502f1f1248a1
2. e415d300b2762480d942cd1b56ccfe91d001c265933142eb8672dfab1d191713

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.