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

c7c8612f7215c2a4a372eb2123cbd422f4d285c7f8bb6ae9d3a3f01c05c567a3

Seed

a884a53694867e908ddacf65e1450c4af0282fdc96dffdb16bec5f3deb380ca1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

47441eab0a8ab9fca8e5f2cf261cfbbf

Commitment

Batch 65,539, Merkle root ebace2d592a5948d1135297162df51f4da7a3e094d59814cd649fd0d3ac315ad. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e13d0d251759f2fdff2842fdb9db11800e48477af24ccb9913650e0707a2fbe2
2. 46b210f9071e98dfa9b3e2f752d0f2f5c7ed49ad0165fa131bf514a1f0f89fa3
3. 2159521ce187ac928c3051dc63a009af34ca7c1431f7bd37c65fc1647acccffe

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.