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

f13db1d343b37b5743b1f07101f7086128a6491b24954271d3fe22c7c65ac691

Seed

28ae3f0df008440fe14c2752e07c2bc313190f57c4db910298a013a6f45b54b9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

000dfc1dacd887e9e477042f1c886508

Commitment

Batch 58,501, Merkle root 24816a42cd0aa30d82f21e40d0cd2541d9d9b5f5faf8c2bca7e69b0740a1defa. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 61bd834c35d576749e86289216344e0f905018794a37ab85808e1eaafd0b78f3
2. b5e9fd12e4a2b4f6b0c7a4fe05e491c33e9293f9a04a821010a7a0e5d95cd087

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.