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

6644620ec76200caaa3f729ae7ef04218a7473bffc2e33ca9dae9dc01c6991ce

Seed

3310d441bbb97b8c91ee78738dc0ade63fed1e61f0e561618bc1f0433febe49f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ae6710f1d8b3acd6e5deef0b0802230e

Commitment

Batch 55,702, Merkle root 24cbceb6f86e1c9aba4fd317c498dc4946377253da06013ac6f4824907f50c50. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. eb0120b7a22f4e3d0a869db5febd1d46861060b35bb94d6bb6f99cf566870294
2. eddd5f883e6f5dc548b400cb506e98d5b8e3e0c81753264446a7d683d8025712

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.