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

bc3ad6cd4e269b9314d63cb08ee4ccd2f502cd62b126b105eac665e59e443133

Seed

4d77eb1b659cba48a10b37dfa00cbf90da86a67ecdc50b85141272bd5fb9834d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6a6db1aff6a86450c2da00ac73ebc9b1

Commitment

Batch 51,625, Merkle root 679537cd3349f06efa7d61d47152a6ea3c3d906362200e72ef39657d2d5bcd44. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. cc37bfc54c9bf5a2210a81d9e57eecfeb61adf0b76eebd81c75f05b4e01124dd
2. 1218657d90af06b9cf3baebec351772c41bc3c59a8ee8b288a8da982b919bb84

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.