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

b809430b799436b720dce562720c935d3db41ddfd5745e6cd21ee61000ba6d4c

Seed

ce3397483c71ed4c91ac121ae7596150e8cc1cbbb7b57c269d83347621a989c6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a79d1e23763fddb546e029e1fbdff2bc

Commitment

Batch 72,970, Merkle root 58248fe0e0c3c120a7bf291180e62d5cc62cc80c0041b530ee898463dd77b84f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 17d66a8c66028141d874dc651109f5fcd0a1a6d74f3288f21271d7961b78da98
2. 9d898f40dd4b3c6c8eec8eacfcc5e457dcd7fd0f916a4024a4842d6bd30ecc08
3. e9dfdd808c3dc6b7dcd2181b1a63e1cbfc017891c9489fbefed47083e1a99a81

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.