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

22ddb714e823ddc26f386eed2babb03fec2f31fd7f48c6354233fad0e4aa2bb6

Seed

84264ee5b2e663b293b2de2aaca1615c3eb365f702bc50ca9ca69d9b642161dd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

be97f630029603bc52b034f04891aa01

Commitment

Batch 50,468, Merkle root 6d3d383a74694c1a1c4a6e7a178c2f924572c94499e6a764ef1fa85ff5ccd799. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 02fa41770a0e0c5d075b4beed767528d12ef388076e0f6d4793b156aa2325501
2. bbb8f72fe4731d045752621b66e30e6c4fc9f72c776a0eaf41398e5e053d42e5

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.