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

0d124f4e5464419a1bc72dfbf0466304ab95e5946a702c849e41705342eb4338

Seed

40377b7d1684f110dd476f37d12deff5c7d8eb346d0488330316c43c27745850 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fc6c3ecd5da51ba736a4814920073d00

Commitment

Batch 71,090, Merkle root d0a5d0fdc656b4dee6822dd1b6a367ad0008f5b7e330883fec2c03252bbf6667. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0364f3be416372d3ab3a3ca300f65691ee8a8c720a5e753e6913c5420ad4abf4
2. f8e7f9f56865f2fc56c324779dde4dab2155896a14be0fc5544305e2005b4a9e

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.