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

1575aa90e97c52e90cf585de9a25f3b12abc4cc65ad41b9ebac298ab1465560c

Seed

c071ebe0c0c0e5f7903e14a84003fab52fcab2225db7c4bbed9aa46594378d38 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

436c46f4799bef07b3634065b7a3614b

Commitment

Batch 51,164, Merkle root b25dddbe0a7b2b6ae51bc37c28e25a1a43e418fbc8d29fb751bd9f1be06b2b84. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e83efbbf21aef4cea23e16c2eaff4d0d8e280deda0dda7459dfe1848a320c0d5
2. 5ea68c633b301eb33d0b52a8da2c1b73dc0b89243f7b2816091189abdfcf1744

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.