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

9dc48842b38d182da8f0792467bab66f16cc1d5091eaffa87cbe0cf6d3765b8e

Seed

54f1cb5dffec3f04f98dc42cfaf55309a6f85aa1ed7fa78a5057fe0f25cf0d24 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1e59b1821fd8494168c27e4a7679067e

Commitment

Batch 52,603, Merkle root 55f9255d4a6b5490334b89b7dfefe63655cc7d1ae45d6e5d456e819074e163eb. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3c0befe2725b1584c9c03e8621166894b89a99bbe71ee5a575a45f4871ada877
2. c8f8905e2df20e1a633e67081219f94e5e855be7645b01bb62b75d6024e9bdcc
3. f381bb5219e7624b23972f70759b236bf9e1e668da9965b13a521ad1138ae851

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.