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

c1df5e7acc395f1bfbc534dd362fd13d8fc0b748920524dc24ab1765f1d09672

Seed

023a62cc11a211a33fea31fa9781f08f6f721251c5cf05dc29ca0e31a7776227 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

48dae90c188412695c3588d98690b689

Commitment

Batch 56,812, Merkle root 46168c22242616a26628034f22153bd7abbf3cdd3db5ae7809b98475e3f364d6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d20b54a94abfd71551577cdf605072773589ebb2ee0de7668c5ee108db8a6e34
2. caf711c1b0e07e50b62105d24b86e5220ceccb47daf85137e692ad991d250a8e
3. a13b48278f8c5240aa7a4e24238937247ef2643bd7849c6ab7cdb5c220a16f9a

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.