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

66dca8c9c6a220008520ae19424bb4e27bd736db0b8ea8cd724f5a61319e8670

Seed

ef00856424f0e678df44c6178305939d73dfe3efb6697a3383d4f4acf189c448 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4fb1654e4c648ffae028a3ba047b7913

Commitment

Batch 55,764, Merkle root 4c7554982bd42440fac66b6d38d9c1bff0b6b959c6c41a52e695a81aad457a8f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. aeb4cc5091e2c200db800d80becb538f3a4baf31a25a606ba5c9d85b2b3aa997
2. bcf524ff73b7d7a7202e30023d30ad8da4561cedd45e2e060098991f548e4c10

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.