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

c7a736cc6e8a33deae8e45def8bf604a256ee93b13e27795aefc13f048e4380b

Seed

e57a2fc34faca5fa17e45b96a40d719f3f17c5a23bf7b5dd785458f7291b5d5f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

eaf789184ccb4326f48af4c68b0518e4

Commitment

Batch 64,573, Merkle root bd86035fdb8e5ddc06275c8d538b3ace56ecff9d0bf5a1c51f7e317625833a7a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. cb5d4f210d9acc8de33d7af693dc9f3238020551862d9c9fefa6c105fe882b07

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.