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

d27d1e5b89dc65d4cfe1a6e06347b529738425b21b81887bb74d2c6008f76b43

Seed

e8f2f585603238b85faabb3f0b1146013b579ec7c8e8dac798ac363955e15ef0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5cab91765ddce2a977b654d28e7e0ddf

Commitment

Batch 58,880, Merkle root 54c837fe3cc64185ff90679ae04119dd31ec7ad2cd2d2d290c5123cd68be06bc. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 502b65e26acd2a40d19ef5a29c50c4bcf836fc6d30a927744247e2c3a0c911eb
2. 0b6849dbb36a40517eb63d1676c89e6b33b48d275e92e5314151f153ddba0871

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.