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

ed5869dc537bef1b98f549d496c7b52046ed9a1ca407d68135141bee4a18a4ed

Seed

414cdbb5f4f7ddbd5ddf54e290d5a5b587b0b27dcd27b646c00e69da35a05808 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5f3389abf9a8a883452afaaa9f464e30

Commitment

Batch 55,869, Merkle root d268e327f3553250c5fe07d60eadf58250de5001e9cb1b1bf31daa5ad0bac3f0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 72186f2557985741c5d6b6d4810ddb39f17e46da2640696dd14fc35ba4187449

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.