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

9e9d4547aa7f2e0a23fd625ebc0fafa3b789c07dcbb0e2dce529fad0193bb8ba

Seed

5f12978c78d3d9da646055189ff0fd1a74155822bd886a2ad567a3b80d1e627e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9a6f685971c7963d4e026a351f0679d1

Commitment

Batch 47,402, Merkle root f283ddc101fcc9f29ab22606af060a6abf575901bc8c205b1ad924e3387b141e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5195f7ad0febfeabd9200d907b7276296f1fd000038409e833da837ec226a4ef

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.