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

2c0e79ababfcd9d845bee04af94aeab38aea789b555cf17effd9cfcbe5cb77f4

Seed

5f49c051e5a35c4e400923c8a7d3412ec1da76ce32bd4e368c99633e0aabad41 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

40d8ad2c6cba76beb6f7110f5e807d13

Commitment

Batch 51,396, Merkle root 3b5c8d7825b118abac9f929fdf560ffe1a1e6d3ff9482b40b5e5f6e840839d5a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. be85a8d776f39eef04170eff206114a85172189f8b4575c2125fd7e4c1740627
2. ae38ed5e063221d6ff47f0bba66c40c373472f81ac55d6ab77167d07360feff4

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.