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

b9387f232a27108c64db0d6b56f1c92b1e31b98ce3b222d874c54144bf1c08a0

Seed

9524bbbf8ee43204fd65caa932a3ca987ac67e9588caf95aacd31a57927c3218 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

86221491354fbb3424837b9946da85ff

Commitment

Batch 64,908, Merkle root 2e622d3e09fbeb5c43f3a1fa3c42158e4f3be0121ed83e26738d4a6eb22139df. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8c4d12abd652ef5e4e93044ea398ac54cbba89cdb5396b439bda3d51b1f40fc3
2. ded17ab19c661830e50199e26199f1604a2055f65b48078ac90fd922dd47900e

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.