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

7be836fc1d6e3d151dc7bd7f74dcbee3caf0a724c8ca1ce49b5f1df9b7d4f662

Seed

a0c67cd71fff4ba4080f051792f86b44264899a80c24d2076300e8f5d7de0d92 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2da87c9f94d9156096902c00b8aba028

Commitment

Batch 53,885, Merkle root b937074edab0919b93faf19170bede84927d71b581e3e6f90d3a2eea459ab878. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 577f249ec139290f5806298c3ccff3460552a7f352a1f4451fcad6cbc13b3165
2. e6c49cbd713bca02886fbc5f2f2718466bc86267b1d6999d8cf7aa7bebe28152

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.