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

b218179d6aa994c01d75283a4509506cf30b611cd9e0e2b5f6c80b64d811454a

Seed

d8e7e8128e6f7921f3f02f239714c7f6428e4592e1d72846586489958543120f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8966af6a38025dc90dfbc8187b7fdbb2

Commitment

Batch 57,046, Merkle root 4142be5e158e4868677d55330cf649cdffecd4c743d2bc2fa7796b7492d74a88. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f9ebed58fa78684809ec6512528223caf111f0d8c91ad337419ac4caf25e5a9c
2. 98b289b04a0a2c6f9d2ac6660957e63bd0490815b72103f5fa506171bddc034c

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.