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

5af59c23add870c14618c0655add50aeedda8d2baf92f9b64f7e7a8b6633639e

Seed

0293987fbd993efa3c79386f4b1db27fbc9ecb7be2492d09aefbedd9b8124bc2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7372806ada9826f080e8310608af1b68

Commitment

Batch 59,537, Merkle root 63dbdfd6e76847f0a9d23ad0d46276f09f6267e1c8ad88f4a097ef444d95f255. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. b5b14adfc0bf4efb5590f0436105903129171a7cd784776b394ea9b73be62d48
2. 69b3438995acaf79d74cfbcf5eb6437139eb89d09c26c147c561a6a79d3e1a72
3. 107cde85a7606ce900d1dca934cafec769ea6320fb92eb5bb0abf10e8aa3743d

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.