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

489704cde78b1f515c478b2276ffee609ae105fd1c67eed0fcad0c2247787ce4

Seed

0155d7d4d0d07b065d2c2623406238c554e3bca0505aede3773b2c2b992456c5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

67dd16931dd789211e97f8964f29a536

Commitment

Batch 52,574, Merkle root 614ab8c7fa17f577c692bf2b429b094a892973284a467da135d15e92e33ea6be. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 280bdb29665730b8f8b2e940bc399596b42b5566cf47a01d0cb21205f3be7e91
2. a680ec75b60849f9d2bd6b12da78b1191f01aa49bd24398e5b2b42e356d04e2f

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.