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

6314e2fea0030b4a0835727a7c55ba82cf49c11ecd570a7488911e3f161bd1c6

Seed

baf210e6846af111f47f473c93a10a91f363dba90733b252a616e25827cbbb1b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

380f369459369b409f213eae47116742

Commitment

Batch 66,290, Merkle root bdf0e6ed49cfb37a1b4d67573f53417c162f65b1aaee8d8b7e1cd213bedf606d. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 96e4d5c2105d421035321e6adbd097c89713b9b242eedfc4d07c9e0b777a1dfe
2. 30ebe13b580a8456e0d091c01f492f99f13cc9bdbbb95d2ffaadb547f9e12bf2

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.