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

b39331961b1dc7be2ca94fc22bdff0b52b0fd2a7c40bdd1366da48dd87692908

Seed

ef323a027c7f7cf8055c9da0ae725438e1c03b3d48653a3750aba1b783313c76 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d10d8cff8c1552bff0a8e16d50904e66

Commitment

Batch 49,137, Merkle root 790f48aa87f5eab12164440f22c31140f46ae493101c642a7a0e4ec6801edb16. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1862c882dc4a19ea8effbd1cc554bcefde9bd481d55074ce8d1ef85470e2addb

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.