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

10b2504629b119208a93a1e7c7bd6ceb2bfb6d8045355f876073c9988063407b

Seed

36b213776d173cd6e1360f164899278e06a4e1e67ba409e7a906676fc00b79f6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e0de105c300b39e485e31b226d931f32

Commitment

Batch 53,187, Merkle root 55ebc60c4ec831543f79574a8bca382db12af05d1e3a4c6e1390413e352adf52. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 6186cade9ac116f9e75a625fe67291fc7eb2b69a87c3ae9a03c20606dd100e92
2. 194f7b816a898fca9061d1062455603cca3f75e1860f8cc36ca3367d60574474
3. bc445f7c73041caf7aeda3a242aa6b044c0de22b1607f0594b929c812571d89d

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.