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

bd226c56fabf1b48d69a4807d044c6152019e5c149e653ce972a63ee46f35582

Seed

e9aa961edee25c3d3ba40abf0eea6e043944a6f3ce4bec2de5377f718df894ee SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5e72a61efca551d35cc8440bd67d7266

Commitment

Batch 54,362, Merkle root f14204111b4137c6a22356f50c37196e0866d89138594e7da7f0bfa0a42e283c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9f64c2d7b337e88717bc0c77e579e79d2814f3d3c75ebade7d8c7e319ca84575

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.