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

df4d14e4f212cf213a5f212b87096ac0b24fd77421f03ca1a6e3aa16a4b00680

Seed

a2faa3cd395a6d6585cdaaa15039c9317061461d3421cebe31134b33cf0edff9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9c046dc7567aecfccdfea34086212183

Commitment

Batch 56,878, Merkle root 69862c9b8108c549aa5bca381f4d2390d3b98a2c2a9239fd4dbb9851e6f193ac. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 6b6f288d42e16242a971cf4606237fe759ce504bf44195914c3ae103ade4dc06
2. 9d640f1359bd4feadcc22a1875a580a01fb555367852d9ba89f385cbc29fa04c

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.