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

f11f70937a13d7c9ad639ae3e54f06f76db216aaa9f3f6d0d48d44dec48acbfc

Seed

0847d0db7bcad9ea20d1e311cafbc770a10bcbde3341e0004fa029f2c9b9c6de SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e18c0daa2f85eb40e027b71dd4dd8c8a

Commitment

Batch 60,599, Merkle root 2c401e8901ec434a61c6bfbdf82955f75535007e41ba27fed0c3cccc83dd2ba9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 2067371afd5c2c1a4a269b10aca6e5066c92fc130e721bc6483a64c856d875cc
2. 4f1e629680ffcc2ddda5ceabb19a1cc569e3c9f3b60f8e1f3777f775ee7a7a4d

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.