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

58b4c57f25d3c7dc9cf3d187b4715c20abe4114da5a3b73fa971121c796a15dd

Seed

8c3e821f10926324aace9fb8c8af8b641a7346c01c38081b32902a4e94089a17 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

926a6a0bfa4f02bff90b5a4e053358cd

Commitment

Batch 64,144, Merkle root 9c28031c4719bb172cb2edfbf1a5a11629a9befa6c29db14a55a72977ae91bce. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1ba3015e4fa872ab6132de21ce92aafad7e37bec5d757e73d85655238e2d56fe
2. 1f0256469a76e61e1002fefa135a8a057559484b816f0ca93862d86e575100f1
3. 52d38cadc7fe97e47f43c3861e7bf56be804e924909846f5f4517e5a991a17f2

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.