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

66b60e35057ee70be65c05158bc70a1d8f9bbade225495fc9191603aea9982ba

Seed

3c297243a8daec2581fd864d9be09fbc84e92e4ee0f3db1482cc38b3ca610b09 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

866af43783920eab29f80e00d007a391

Commitment

Batch 68,029, Merkle root bd296ff26e2a8a6b20b6e426b1c9ad03fc165d77b7a5a83fee61dfb5793e8eff. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 52bc07cd1ed09b75c2fe10b566ee49a31312e1af70c4c9a8b50d59a81bb44b6c
2. 2b4cc213b33cdca8cf6d9eaee3b5b8c74674ece9405dde8f93bfdfbbe56c1a44
3. f1f10ea8f037bd6fd3d065165676b0475fe79e4bdf7e15e7ac5380d320426c88

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.