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

f843bfa7e1a72b40fb024522fa1792d9f481d9af728a68cbf86f5a0be0dcc02c

Seed

b125c7f645b8b21e0b59ed19390f432555909b94f0c6c58fdef61c95061ab0b0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

aa4a25f42369b7256388429b8982016f

Commitment

Batch 67,098, Merkle root 25a3e7cbe7f51c8706bc90e3d1a6b9e0ff77849d52113d563696c4fbb03f56ae. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0b42233d0e6ee0f806dc736b65aeb4bfb9734f73dcf76f9feaedb8b49c62bf41
2. 35634c641bbded79a0cee85bd04793aa25f4265eece28b4a9733729f30548667

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.