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

d204b5ed10ec8d45e341cb96006abbe164c0014f217e459095253cc106a26bb2

Seed

aa89f1dcb944e4980212aaac63600096e5cff79cb78aa4cb36b7609f4b53cbb5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4844b03e64f6eb2fad5be2c747b5369d

Commitment

Batch 48,089, Merkle root 7caaf8145947574dce825105ae90346732337c6590c3430d9b721fe1a1588270. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 2beb378f9599b06ed33edecb199e9e38f23fd672c531f68c055508eec1f70005

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.