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

6ce84e1528b43f96744fbc2349f182e932c5b5bff66326ac700a68ff291c55ea

Seed

6c824181e51c8c9f304845aaad2c137171f8a8b4512927d1364b0317adca13ff SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

94e2467276956dc59502dd1927d8e008

Commitment

Batch 65,100, Merkle root 943dee7bcce5fa43e9fd1ad36e4c4d794e4e81cf08dc6ff79eb35868e7c0c224. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ae799c98ca28761c67f147083e9fa8b2bd4688bc48cdd955693b6dc7bd4fd6c3
2. 3d1c1c632ccc5107b8ea145e766a6bcf643f165634dce19cd20a56238b240063

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.