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

0c23cd4f36b5ae06c3d65e984df6eda5b8d00a086a4cae9347ccd1ea99403143

Seed

fc5e1c65a17a883974a64bfb33afcb0562b3f172fd21dcfd392d16c78760c0fe SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4e7dc72c0449bad08076d3b4ff33b752

Commitment

Batch 66,980, Merkle root fdc735331e71b931fba49c97069c20fdb68839563070da8a92bf878b1316d27e. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. fed895973f7355ac669f536838d521103c9809fd8dda65d22bae40f35db4bb24
2. abd9e4363bf58de9f33f78a47dbc47d145c79fd2ecf1f3f104429a2e708e82f0

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.