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

30ab40578ff306fd471ecd6b9d69072b896221a2129357ea57f86ea97026e7ba

Seed

e1512b5074738ecb98537548fa9e3c42e8f63f5e9f3bc6894777b6c893c28071 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a82bc12c4a2803cc86ca83c177383e6c

Commitment

Batch 61,408, Merkle root 2417a98a4e1ea8d90762b8dd7ca06b1ecc3ab864a0818efa8c6e64f8dcdf5280. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ab0d424627f5e221841a177ee7c7aadd13d8f45261b5640aebc22f92becc839a
2. 444aadbe86b80f0ec6b5d5619b27186e8a5716f35a6f387b781a09c0973b84b6

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.