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

90fbc0439574f135e17f3f153e94d5641fc102d2c19b5482dfb759a37c128443

Seed

3e2f8256a562c89467791a51709cc8423476794a61d9502f2f85c1201c7d640c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

36742220de76aa46ae0128a7f05e95b3

Commitment

Batch 51,589, Merkle root aede32675e1aef3ab6d0bd435a1343ef7a513958dada2b200f0004a235d163f9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 14a63434c78faa5b4055c54fa84c3951f03b914f656d0469621403b40a36b0e2
2. af1da977cea453aa3c9d7d99607e6915b4728663906a2591ccb5b1144d61b4fc

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.