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

e3c72d8798d1dbd23768a93d7b023d40d03896cdfb6746ea1459c514f09b4893

Seed

b0a766aca7048e29c2a6d5c75a6a58d4574040fe2d8ca495bc59c181d7e72bd7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b165fb8c1b6725752401ccff1a1d3ae5

Commitment

Batch 62,889, Merkle root b7d33d471241a01fccadb303203dc417d9ec675c79ca4eda4578d394217b3854. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e5c9e3b531ba0721bf0594050bb41a5d2bffcb7894e0a773f9cbd713e7a74e54
2. 3a48832c8e001487b63b2ef2fdca63a3e35c4e67fef4390a34bc3d0028e73c1a
3. 848185921d6043352b54870bba895376660bdb1d32a1cc208319a1d2359e5f7c

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.