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

89fe1a8433ec5ed42110d3162f2c8c68eefd2bbfb4b11f6fc897dcc8a0334ea4

Seed

1ceb4b17ced337c92b0897aec4b23aed03520d749a03edef9140c4bb753ce3ee SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

251049adb2b931fc80a577f994e7a2f5

Commitment

Batch 60,718, Merkle root 5def4564e1726c64b6056b304dd28099ed9b69fa8ec11c2c67d5b9bccec3c8a1. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 106f7222a3a0da8c9b9fb4837b50a35517b6df135a17e00d58f94aa1873c7a69
2. 151981c49caf1b8ba0dba0c5b0da55adf3f5875cc26da58b30261df97ab72cca
3. 0243b52dec4117d61f68b473b3bfcd1d4cbc3b35335f4bd3029984c6870e8d14

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.