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

59b10c7e57ac8ac9362fd2a86128ebe4ace511610495908ced8157cbc22705a6

Seed

8cc5636d64ce3f0803422b81f6c9f12db67bcab11de6f117477248daf842a567 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

61b0d3f44f8f757ef1e5faef54ce949c

Commitment

Batch 62,290, Merkle root 338ee0bef8bc3179ca842e209a0a2ac1d29a835a1a3b227d0b2e640f25dd6d16. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 264777e4f415c249dffaed3b88ea18b23961014662a4d35ec1f7a35955114f07

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.