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

3333bbe0bb912a57bb1da307aae0a34c82ee4548831eccb5c7eaa3b11e990f6c

Seed

cc452d1965a035de485f64c36bc547ab51ed99d24a9b7d223f0125be491235f4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2f493481a456d6869ec1ab039f5cfaab

Commitment

Batch 55,817, Merkle root 8a0ea8659f76fe7f23ef94d431bd6b914c4bca1ee4056a9db7dbe9d609d75e99. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. bba5b643c2e7d763833d81e594186edc7f2fce14b5793272f1e08e3a66d490bc

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.