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

1d5c1ed4c47c7ae19f8828de8798799bd72ed6907975c37dffdc4cea6d5aed93

Seed

4e01aff3b50fa1035667f2ca4ab6a706fb868d31e366eb50bba9a8d6125671e5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

945a9108b34a35f285729b3c83ba422c

Commitment

Batch 73,019, Merkle root 27199af5edd3eb1cd5ebbd45499b8742080aea86f7ba2ee38779cb1275fcb27b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 6bc635624220ad59eeeffa1201a9d52a6035be0e68b0c5e7bd75efab169352f5
2. e7383b82f0e99ddd49d5edf15f1dfdb9601395b9876b5365eb5876b4dbeec884
3. 41fce8e22831a507bc7e3c0d8a5fd25c26df4df0fa8942b87a6ab62cdd96834b

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.