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

1ca45c3e8dd0c82555b2fad5fc9e08d9490bbdb512eed16129864a3d6e7ae573

Seed

a09e2c66102b0a9ead3179d883af37a9cc2cbfefd3c55cd22712f4aecc0ca3c4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

63f3d449487c88e512a112c6d7b4fdab

Commitment

Batch 54,395, Merkle root 838c8169a58117b6c0f5fc47d4c3a5959de4d8d56c20fdd15bf72a4920484bd0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c1dfcd7b81f9f97ddb770254316b9b0a4b1511f5e8ecddf52685883a160e2d69
2. ef2d01830269c5c6af8c4a52073c843c46f2eb7d349883375b03aad2ab3427a5
3. 46de35cef4c00268916134b4acc5d4c7537f36ce2dc4cafdce5b5287fc84ba2c

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.