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

e035ad41fe826c18e925f29875f55a48a9f7bd86eeb7b3ee832455d190597b3b

Seed

f06fabfdf3b4b21f38a142e2329494c45b2616b1c4dc0e5b372e18231f07b75b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0eade4f3c8e6aeee68abdefa5e95f340

Commitment

Batch 56,411, Merkle root b1ab2fb42be13a7322ad9f0ed03bfcfe5ccf7e5b8b9b62493cf09f3aafef26e5. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 304199f725ef92fc8baf76f1a7ca36f118991d56cf1489d253d9dbdf108ea75a
2. 821d91fa16246b1b74564b6f25e4ae2e97096963653af38ba592cad801fc6cc0

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.