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

9b2b7e4fc88ce14c4bec88d94818e14831693da8999c08eb424c0de9678cb4fb

Seed

feeb9022b489eac7c9d673849c83acd9159ff8b51a31d231930306a3abbcb182 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7815f25bd4db8e28ef6ab658d3f48708

Commitment

Batch 68,599, Merkle root 88ccc75d0c1b184351680b4b4502b2a77df0fb0d94112d00bef8fe81c55fd55d. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 373b768bbb48e7aebf920a148e8102d2552e455a9d2f35b391b36e41950ee0bb
2. d920cf524dea232a2e94a6f54f9287b98dd6840417b020f5eca2c618b922ba4f

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.