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

bc01ced8e48466bf947fabe45605aea431df18fbbc9653116bbd55d29fc3420e

Seed

a7ab95d2fa3a261ae08bb8078ccb101348876be7b861ef33c948794f15670388 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

10a75d6b7807e502a4d8be3e9b0623d1

Commitment

Batch 51,706, Merkle root ab6e7ff4f0ebaaf485b160b98c5fcc258df1a868827beda93de7dd6b624307ea. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fd2ba4143d62d40c2acf04c579e15b89dc1913301833ceac2a0481eccbaa8061
2. 3f5b68092889aaf4a2b1ada3d359cc2ccab09af3c9d8bcb9ea0a5dc127951073

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.