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

70c6f2b83088e8579928739fd7c4cd43f8e009d139d3a9ffbf7c73d74fb3d325

Seed

ae9fd7d3d46f6f876150fdbc4278c182c658da14d2e8428f479efa9d2236af7c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

676b6435e57a5b9b050b722301ed16ba

Commitment

Batch 69,370, Merkle root 419c9ddd6fe496feebd00804d77d9e9ac56491896ae5bd378b44223d9c17677f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 555f4cb0f6c852811f25e96ace9e6a6d64638d1013188431460c5a2ca09f88db
2. bf1c0e8227f572e546418b60caf352052900d6f743854ade7636f2b90efe73be
3. b178fc6c282c45c30cd35942a5016ee8179abefd8eacdc259f9665a52aee0038

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.