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

a23e3f5214b3a9f1c62f1a11e7096752700f85133b5ec472bffd680d2c397b2d

Seed

3a096ca2578a43e437843e9877b90590070b26b0f8855a4c211a68313cbeb83e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cd28aadc6f93f0f1da758703a91e5e9f

Commitment

Batch 71,066, Merkle root eb821a23c478b8366807b088dc3c3b33dbed86d869354b0679ac030f3c8f1531. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. ee0cfe9bf7687db499c783befd2d5874215f3fb9b59995b78da96cfb11b4ae96
2. 46c84a1b2acc2f5e70f5a1cd7a4b56f68327feef3824c24b9d45e6541e876f70
3. 9acfc9ed51fb462f495d106ad07c6abd9905472f6c58a5e262d7bf4c89006db3

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.