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

1973bac6f5b97d26c1b95f8c3e7e304b5109a81269c20348bfecfdfc7964b036

Seed

7b096652bd1b49f244dbd552f39bfb5d1062830509fe35e6e465f517df7e3d0b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c6520326d463693ff86b946d89d07cd8

Commitment

Batch 57,253, Merkle root aed49d5bfe249b3c6c68785ea1c964c12b1fa10b9e923725bc8b04600f13a8cd. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7c00ebc4e3e242597049891d92e1ab2849b899247670764cd40b8e177f2055d3

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.