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

550b0a51ed6e89e8f1cd158c436ed27ce2653b5ed4f32be05f93f81cfbd23ab7

Seed

bb8b43252b51f7822b4c51a7910823d59f3590173a02ef5a4535781c4b86d437 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

072d72503a0667292e090b58a9adce81

Commitment

Batch 61,778, Merkle root 936a430e79767f635f452960f0e9eb85a096fbea90b2dd3aa6a16d870990ac5b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 10dd7bf96ffcdf58ff2524e5eb96d5542bec037f48d85312d1049bb7ae50c848
2. 659a5365f207e95c2d5fefd096f4ae378f6fa8b960658b2261892e5654e5e2e6
3. b8d04737f213de0fbd573875639f799792146c4496c3dbe54719eca0296bf021

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.