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

a91e39a062e8114c36725fb838e62c94a51161b91572a66bd6f2557b8d356191

Seed

3368f93f70dc66e869a036591904add1089a1e901840e39b8b0108a314d6e3b3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5a9ac15ddc3d0cc90b8dee47b238a129

Commitment

Batch 56,696, Merkle root 52be87210e257406642fd355bc172360a493f1236226bbbd5870ef3e42a1da35. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. b0c92c0fe4f9e95e90c47b7e676bca4475d531f9e4379fe01057de975b0d7b87
2. 670d11737850fd22de0c918fca5fe5b584cd0c8526a3d773cb263a3517e406d6

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.