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

af808b107746d0fbf2baca363a76ef3cd9a51f4721325efc1ab5403397574786

Seed

729fe79e8e5e9ba0dfdea7ff1ab62a9a0f3ffcc5e751f476843e3a4a99ccfb18 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fc4607e32f7617ab92a32f69294c77a2

Commitment

Batch 48,749, Merkle root 4c14696b314853b18dae9f1a633958e072926c979e825b6699ccda5b210b31f6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3284f8d2f34db29dda3bf770373ce1c73fcf372323e41b9a116991d64f3a9d18
2. 5045468fc81c7b621db6f402bfa96ecf46f9c1f404b63401a48a33ff3fcf9be5
3. ffce99629f22d4af770d641b0fb4eef06e51bd02949c65021fa038dcfca40445

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.