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

8c3f3e6505f70787a2ef8aa9623a9b486e9ebb8261c2756639841ce5bbb1c0a8

Seed

f40bdd7656444e4704a6bd32d7a63cb3d344b606703deab05cbc8c4bbc09ee45 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0bcf556b740d19882d6f64a53623fde9

Commitment

Batch 57,976, Merkle root a2ffb90023075f475cf9f7b2cdfb709a4571606ff794b53991d537850bf52fcf. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fb563ea4997e81e8a19b23fe102beeec55c70abee50c51f27009c929df8b361a

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.