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

663d29a9bdd5b34349497b2ee8d600f5c516ccbf7a90f5f0b9f3bbfc62f58b31

Seed

99c5f8adb002a58632198a8af5d92b670264978d25e22b754c161ce977f25af2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1dcb2a29ad6665a1c68f3631746c47e1

Commitment

Batch 63,681, Merkle root 8627b4324a016df1251323dd58041d4e8ad894d61e564d09cc508ec28f87cd8e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c7edc011bcf94427cf9b0672774e16f2a46d3fb2a2514d233a92e49bbecaedd9
2. ffc3cbafdb13b258088a49e52b1a1a9890d508972443f30bc9f8550777345919

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.