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

9a71a039632fb1ef795b730ff6f399cfc2683964154f98c5c918c865f1ae7f20

Seed

ae2bc698fa6ff3f8f57788b60683e787ee5489370a7dd7284ad45920d228eb4a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e2f2e38ccd168aa61ca974e8fb134017

Commitment

Batch 59,298, Merkle root d90512cb94e9e960573eca7be8809f3f98a1783e6e1a8f6c96319048056bdbfc. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c8b7a9de45d516d8c1bf2dc0055840397ddc8099107ed8a7c3145503a73e6987
2. bc35b7424dfd48fe20a06b5f572df5c9a83a1e478434a7ea0035607b6026aaaa
3. fb4752b1e2c6798fe6598a2613a34f784bf4ca6186d04a8a9b3ff715b8eb4294

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.