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

252e8b3ede2bdff3f3970774f00c1dcd66809993863105153e1726df15aaff2b

Seed

cf268245a1f3dcd3551bfe25bfc3ca7ed16aaf5d5b993d48dd27eedfe5517ac0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

50c1d523ec7081a8e6250d10ac8c7819

Commitment

Batch 61,997, Merkle root defb6ae1301e296718789fe90df098c4f490263fa1ac6769a72c83ae8289eca9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f70ef143f3381c8149a10a71a2cfcf7137cdc4e1e85da86cff4932c5fde64ba5

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.