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

2048d441ad8184ef0a958d387f4a02d74bb4172ac6ef9e0c7a0fb28dbe18cef4

Seed

462af9b34ed33038f7046d2724e8b904f5622d4d6699b83c25d9e7fff1462530 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bf2fff3ced383dc003105a945a7302ff

Commitment

Batch 52,130, Merkle root 9b83326cad6acc0299f21f60862db18fcf878b9942bff7e553de6da8bffd3714. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 54146a5a7a5980010ab9eb69967d18329b4e8aefbcc1032d6834392d0e4a8c5a
2. 6fcdd70d1a6b7523f734a803ab8ba57f34221153b95137c0475586ef5adeda92

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.