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

39913445eaef6358019e9f364c0a2eae8d7e0a78da639ab6b7737108f290af12

Seed

3704e588e9d63daf7352eb5685a5058c4218de01d10c6fc66e2574fe48b749c0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

43cecd1ab576f360ded44e51004d9bbb

Commitment

Batch 72,044, Merkle root 4d8ce50277bb11182f22d899c3bc9239cf84049ac99cb8bc189622918cae5735. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. eadbb8a0dbd8602581b1ed178df8ae546787dd37eae79a49aa1b8f0b354a7570
2. 4f2de5323af69c95026d513cc83a9e0cb8c6d7030af9785b2daca04fa015e05c
3. 437495fe8c669dcd75d12e7afd4a66a445b21db084ff48cd387326ed8aaf452c

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.