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

9f59689f5e389941fe5800dd1e7ec34efcdb1adeef4058b0cf52d1b08c00d200

Seed

a8bf4adb43d4413b7193cf037b0a68ec18dee37c0989174913133b8bfe6c7bdb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b4b58a1fe76b3b7ffc05dcac7d25bab8

Commitment

Batch 49,257, Merkle root c85fc69ce428cf63e3c8916ae6c8503eeb9cb68b538794ab0832ca03e4548b0a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 58701660bb40b7b4b2faed832f46691d5ea9e9d773b4df6d23451fe6640861ba
2. 38e445b6ed827687c12f412334ba4646a0be1e02b3ab378cab4c60e6665c51cd

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.