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

b11fe41ab9dcaaf8647e4425a49f221d64a38dbc04247d6349be749f1de7c962

Seed

ee767850dd217269fdacf47cd2cda6cd585ad40cb73f04a5047759e516a85cea SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c3b56765c04da4d174d7cc39d598f770

Commitment

Batch 65,304, Merkle root 85a46e1f2ec2c7fe1158c528499d9dc3985e39e14d867c6172cb9efd607c1819. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 4d24dfba583244fb3cd51fdafc1a7adee1f15d1317b1065498154c6537c757b7
2. 6d334fb0eaeb8a58a54e8798691d1d88992a8569e5ab8d14e054ea82d262d78f
3. dcddf841a418457b7bdbdb0374aa81977cda0ab57dbc6a8ce02155e798c390da

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.