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

009fb95d530c1e1f9e0dac48a563b4e12212d551389f4f41ca3f0fe1713848db

Seed

6a9da7d3ef370517837bc9347add9c64fdea0b7edd4e8128ebc9b0395e6246ba SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5495e96c6a446e8b9b2fc764a720b7b2

Commitment

Batch 48,868, Merkle root 13952442ce477ca69012bebe7241638ccedcbd3787101fff52abfad6196598a6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f67717bd33255ae9ad0ec20fc1c83b6acd7e6f03df4e709417ce9dd9e113b8db
2. de2b55bf88bb5960b9cda56cfaab1ab315b9838ceec434a7a153859eb3edf100

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.