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

ca7e8e9027925c56866068f6a9f6e48acb6bf862d3e2ef688ea6b7308eb07de1

Seed

829b2f59f9c8e1d55797d2f0007a3a4f3c52b0f76b1ff9399e18ea62b372991e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

18b4c76bae4d113bfd515a952a623145

Commitment

Batch 72,279, Merkle root 141ed05235e3a9c00186e1a25a3579fb793ea601689b37b58830f58686c71b45. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 1b652c2f33123cd3b55909a565a90e7c8f173d90ddb62d48b481b1b3f778ca6d
2. 1c1b36a8119e1da56afa44df7ebbbbf217318869b8e790150bb5a794602d7a25
3. eed7ed1f84154a11a8a92eb026fcd87dbe03717b93e79b8140e81dd9b8a2d070

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.