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

20555c6797d496181491b0d371aede8688c917b4af00a3e88757c53259302f72

Seed

2fd015b03cd223b6daefa318f65d3c78b8adcca5b45e8fb8e7408a27c2593e9d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0e921c848d28d627187a2d45155747fe

Commitment

Batch 47,462, Merkle root 4a8db32e4fa8b9b64acb7eb1581ffab6087efd1b07f36bf7b220fac2029ece63. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 12584a307254a1aacb662baf6c64ef687efa04af1456e389006ba47f09f37cae
2. d64beec92c48537443826d7eb6cf1660b31b5d87e4067e9c8e9f58dd2b699fbd

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.