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

a9f25e020caadecfe670345e413fa53c950797fc7b273897cb4738e6dbef4e4f

Seed

ff0981894dcb56f1106800d9679d30bf955f7f21df540b386f0f167856608f33 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1a55418f819b5474a9808af10ae0fecd

Commitment

Batch 65,154, Merkle root a868dd92d549da94287314e349c8d6ba9a4856f1d40a6224347251dc43f68f2b. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 44577a3f762640829df1281f98e63d701a054b2c2e4094e3b291d84613d75cd9
2. b2ac0a7739d8dce2b8926fef2e32d98a869f09eeac061e57b550f2773004ba91
3. ba50464ce72a6beac176629323a5132a4596b5ce89640904d3b76324a65f6d8b

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.