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

78aef2ede600f1e5e162fb4a1e586fdbbf3714ac4af2f05db54256855a056e2b

Seed

814cf54c18a0d1100ff1ad723754554439750a8dcb3936e9e6d3f3c3eb884335 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9c28ac7cda9b53f311b1c8a2917332e0

Commitment

Batch 58,793, Merkle root 1a6180b4de73624d449d8e5df38e5a54a4f3de71d58a3461f8b98a2d120ef0a0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5dd84992fb7ae3e725f4c24a2527eae5d20b0faf9974f65a7ade3a5c714e3455
2. 4862ce6140c708d7d6cc9c78e350fae7f55cf23e3e908255bbaae747a6bf0bd2

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.