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

489ccd6522a5839708495b191a826d090b45bbee7e8172a3188a5fb54315ab17

Seed

4402647cdfb04fcb18a12bde18232d5c364c672b84e4630515fd81ae4b7154c6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

442c86c7cb3b2413486501690878793c

Commitment

Batch 58,271, Merkle root 30131d399b5a7db6e3319fae2df0fbdf7b8cde4f5f39ab4834305b3caef927b0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 90b3220e064148dc545129232a5a4c2a1f7d665102ddd0f0703cf687a06ca8ee
2. 527b2df184696a6a6530114e9d5a0e192254014c169b676e00aaa3aff978adee
3. 19f01208f377f0c35867ccc351ec11ec55c8f8e24fdf976bed281e998326fa59

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.