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

941fed2aa23600808eca31b3943104e56342c54d895f10d49338f1ad9b260c60

Seed

21d8354f6081beeface33ec9518da25b9d26946b452fcfac2026adee9774937b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b52eef9da3fc41c5145b6ee1d65a9a7d

Commitment

Batch 53,623, Merkle root 0b58719200ea04e5d29b8187370f9fcadc28f23a1d58392c344e977b472c57be. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1ea708227695d6e2a6500a73ed41caf352712be6ef98a2251e8bb7c92786bb47

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.