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

c4c1735f4da53422220b32505be453c4851e9367aee9fcafdaae2b4928839f5f

Seed

620413ef8a0409e26e0a1262229caf77704b9a83f3766a506148fa7eb035fdce SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

82de618620aa6a7bb766c5119d14df88

Commitment

Batch 49,641, Merkle root a6fc816120b6375656e0396a69a283bad017352337ceb513f37e32aa23ae291c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d00d1e48062df086e7bb933fd22b2f81552e73e79e5260eb24f8709590d6acb8
2. 209f49646f269055a00273122ffdf06d1bbf5e484d94bc0a8a2c723f4bf019ba
3. f09d82240d39ec8f57aa4c9ff30333fb7860498d120c57d01e1d367f940cced1

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.