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

3968d1b79d75af8d9195e01505021cc26589c3bb9f983706b381656e659a7ee0

Seed

0d02610f17e8a1026b356a07789e353583dd3013d2176420443d7466ed70a92a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

05d9064058b46f06842f4502a7c741dd

Commitment

Batch 65,545, Merkle root 315fdab71ed71abebf8f90d0e50aec3c23bc30da5abe8b393c740421f1364a92. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. de6926e3bee274edeee02b9412361f02a04e88486286be112baf91c59cb0a0f8
2. 24b239f81e088f8cb8696f3335d951cb2e8629edd4f917927ca5cfddef91ebc9

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.