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

2b291e49a8b56e0859aa1aaa7deb97c53ce3e6cfa7e4024c1ffea91332e92fd9

Seed

26967e33e87d3e635d1d00f75e6fff4bce1e141009e2d00285062f381213b39f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6cd787245eabb615eb351e040e40b995

Commitment

Batch 48,447, Merkle root f7b25ced2fafddea3532291609d68722700249a66943e1de200c4a29f6102e7e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 6df7f5018f63faaf2330d59d974a5aa1e32cef2f7f59abf38556724b65ea5f63
2. 2503f7cca8d7c357551e2eec2a7e4cd5470db1ed8c7bf42419d0d647b82709c8
3. 12498a76a8663ef13e1ddecbd73cbcf899ba640bb1b6c0531e22d1d5cd5f8e85

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.