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

1121539f0437881f011e9c238174ca05e131885ba1cc0f981da404bd5465ea53

Seed

17fad1e9e5d2ee677d0793e7b493052c7f3d3c9d817147ba57ddb9b8916f67f8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

93f31ec2578cae45baefce3aa868af07

Commitment

Batch 66,322, Merkle root ad00f91f89c270a4e26da40bc0d1d7de34bf6793d4f5a62eef9478e3b34b58c9. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. c9b4d7769157292df4b4dde26ca1b6acaaea824a63c75354fad94fc9848a1406
2. 11fd2432e4c03d2a16aeeff5dbe2fd960e1cbf786c2fc9c7ebf70b7b60b4c2a2
3. e9351199070a67178af0df83ed3b06530a05ef9070465a34ca4f8d27f67899f7

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.