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

9bd0355705feffd2a1471ad1dbf7b7c2aaf5ee38f9ab54aae303a8287a884ee7

Seed

0c7eaa74f806bcd5e91c446f425354cd3014024eceb97f87045ebfa35caaf8b3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1c04dd4052b7d64b5a35eaa428297d0a

Commitment

Batch 49,377, Merkle root 655216f09e35451ccef6ad39208cb2b894e79be9ae873cc9d0fcee633eaa6012. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8a625b58568beb35660743498acee7147ed5c8667a736069aa07d2b44e5e9d73
2. 23a214061ba4c553667f70ba5bdd9d32f9ab314059d433534368aa11da845352

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.