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

98ceb57974550238e5f37abe2da2ed79aa5007eaa86e2a1b88bcdab651facab3

Seed

a027082399c2957b8801d85525c503e3acbd4d9febfd6dee32b4ff594c44b2b1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0d620ad07a5ba6a418cb7e7dab0bfe21

Commitment

Batch 70,616, Merkle root 01541cbf1ab33a97dac6d043a0fe79215a05057a8f7d339df11e46113d014c0f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 803f41d7bfaacba5501e5327d278ec822042360c67217a32f6e9e7111ca08004
2. 0921d8ffff968e64e6c6ad30a1c0f67ff36c186e9969bcb7b60b2748906187e6

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.