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

a7e58073e977e7b8166b5f36d46145071386db6009beef9a80214e12dbbad56f

Seed

743ff2802ed77ee0d397f58a8b167419574135e93a244cacffebdb86f660e49b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

73ca8f2499572115cbb37fcce99bf23e

Commitment

Batch 64,437, Merkle root 679af53df71b81612b06ac89a1de6bc06c5e1d028814174459014b567eab97ab. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3386c3a62d2cfc347b8fbd94431b9406939c7e19e4104a86b8f75dd0986d192e
2. 3b168157260aba0615b32b53569b0e6cc417b70f8b30bada127aebce9bc177e5
3. ebc5fbbed919512933acb84f50efe23187db207e6fe78cb819f55badd757b089

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.