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

b0b30ef7d13d5eb799e5451152dab749105ea0bb033aaf5cef437076d4dc0153

Seed

bf1b6300c4bf4caea3dcfaa6eca75a424fbf98d7293963594366a640564d63b3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7d21f1fd7979e9243b558048b7a9672b

Commitment

Batch 49,158, Merkle root 5ef3ccef3a34f5c349b4d3e4c3099f1e8ac8eb7b202d84256242f1b71e3f9344. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 05dd53031e94e01da4184b5725872f1bba741a01179a67012967a6fc16843ca8
2. 83dcdd4e62aefc0d93b8c011b18f5bbd1bb6ae712a72f1f475884c62d78d0dcf

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.