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

67b62fedd53b47e2545727146b08c9dd5213855f9d780d77ee01677d0eae1615

Seed

b2839d2256812d6fcff4e9c5b3ed0a0d7ce429cf2792a1dbcbc5fe374da1cedd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a61e6b46dbb7a216fdf50b5a2a9beaa9

Commitment

Batch 71,127, Merkle root e4c32685fc1cf02f19be38b4ceaa7d500d433a5df5c1e596d808b9a9d323bdc5. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 78d9f042517326ceecfb0d3afa4929f96f4be2396ee447ae1485a59358dce200
2. e7ee2fd555a0e12d787e6218968dd1af9e3676be83eba8c0cdc08028fd1e90cc

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.