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

e01d8e0e88e62a96c199592b8e41712e22e30c84a0fea8bd6cff6256a13fe9f3

Seed

84c5fbb38be5b80146ddba95748b6bab87837a055904bc52ca78467e523edb8d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

492afdf2ed554c57e3c22b1e079b3122

Commitment

Batch 71,414, Merkle root af9a539cf96b0a9c4ebff4917a6249057a6365565ceca9f4c6824a73a86d09d8. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 37a3fb0b10c1d02ca738a7fa356de2ca545f750d4638a201f3b063d2abba760b
2. 9540c01c02e2b6c82ee1b301cb47110f7aa109db4308bc9a03166c751f6ddea4
3. 61b88d8e806d0833264e49ffda426eda3a7c0613a556699e138ebf02facef410

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.