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

8f391e06a05c662ec2ecc149dcc1000dc69cb15ca1ae18fca4814e337e4b5b5b

Seed

94259923eb03c101ecd2a1dcc7ae0b0b0be9864ed9a113e1abf45ecf8b3c5b4b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

99354948cc3f5f4550371e9411cb64ec

Commitment

Batch 50,198, Merkle root 8c2ab362bea5a0d9799ed3bf7273cd71c42faae3c3398fc13a320884f9669ab9. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ecff7aec1c733dd4dc7d196d60f1f41f634220b3596aad50392dc6cad4ec2cf6
2. 7c5cb8a0d25171ba334a0d375e8a510ea06bfe7f7312e4f0b326e97dcb40e4ea
3. ffe96154364fa527ff9d4298366d4768daf8cad26ac2b2953836c7fa87890b65

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.