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

3e76781d624621af7f7993bef743e39bf6794c77c55fcab9d57916eb0b2cb5b6

Seed

656adf97feec44cd558d553400fd0588dd09fdff93710d9bb4c9893f4095b1bb SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

99213a438c4cccddfacc9a93347fedcc

Commitment

Batch 54,512, Merkle root bb54bdf95d913d6a20a5abe474a56a91b2e84237792a47a5d749111ef759c159. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fffa96b9b3c2edeee67a614a8954219a1ecb8f9e35fc3ca3a380ccea31bb48ec
2. 7de57e1f447755275a453b292e68025b40f1e7cf3ae7d39c35a96fd34821b04f
3. 79be5f482ca2bbd708ef5a8058397dd2bcb647d8d7e17c32f87abf79ba41c3ac

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.