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

66ca6dba4bae76cb07ce20ded28d326a217ac69e44e28286808e951ac1814c5e

Seed

8e051689b28231231e818c5870cc29e4c1004caf847eb914c2873d8c4e45d566 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7678046d48a958907c93ec5cfa375166

Commitment

Batch 71,596, Merkle root 8a2f6a37a64f5d96d89c021b0ef063174e3d4a1590d052b78a79e7de5b7c5402. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 4d4d8e647de84c4e5d50ca7f107416ff34da863b4b546aea233ca44ecbb177bb
2. 135ba3c923b7e2c6d1cada58526e71ca5af1322d8a74933117111bf683956799

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.